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MEMOIRS. 
CARNEGIE MUSEUM 
Vou. VIII. eta es . No. 3. 


SOUTH AMERICAN NAIADES; A CONTRIBUTION TO THE 
KNOWLEDGE OF THE FRESHWATER MUSSELS 
OF SOUTH AMERICA. 


By Dr. A. E. OrTMANN. bm *. 
Division of Molizcie 


(Puares XXXIV-XLVIII) Zectional Library 


INTRODUCTORY. 


During the expedition of the Carnegie Museum to central South America, 
from 1907 to 1909, Mr. J. D. Haseman had as his prime object the collection of 
Fishes (Haseman, 1911)!. At the request of the present writer he, however, took 
particular pains to collect and preserve freshwater mussels. The result was one 
of the finest and largest collections of South American Nazades ever secured. The 
value of this collection is enhanced by the fact that a great number of specimens 
were preserved in alcohol with the soft parts, and the study of their anatomy has 
thus been made possible. Preliminary notes concerning the most important points 
of structure have been previously published (Ortmann, 1911a), chiefly in order to 
set forth the affinities of the South American forms with those of the rest of the 
world. Only a few typical forms were selected and discussed for this purpose. 
Further examination of the material has revealed a number of additional and highly 
interesting facts with regard to the anatomy, which throw light on the taxonomy 
and phylogeny of this group. 8 


1 The references in parentheses are to the papers found in the bibliography at the end of this papgiges 


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452 MEMOIRS OF THE CARNEGIE MUSEUM. 


The present paper is intended to give a full account of these investigations. 
Naturally all accessible material has been included. In many cases only shells 
without their soft parts were available. This remark refers largely to older and 
some more recent material preserved in the Carnegie Museum obtained from various 
sources. The Haseman Collection likewise contains only the hard parts of many 
species, but on the other hand, other accessions consisted of shells with soft parts, 
as, for instance, the specimens of Anodontites crispatus from the-upper Magdalena- 
drainage in Colombia, collected by Dr. C. H. Eigenmann, and a collection of a 
number of species from the La Plata in Argentina, received from Dr. A. Wind- 
hausen. 

In spite of the comparative wealth of material at hand, in some respects our 
collections are not complete and do not permit the deteemination of certain ques- 
tions, chiefly taxonomic. My greatest difficulty has been to properly identify 
the “species” at hand. The older writers, Spix, Wagner, Lea, D’Orbigny, Philippi, 
Hupé, and others, generally described their “species” from very insufficient ma- 
terial, and the author to whom we are most indebted for clearing up the taxonomy 
of the South American Naiades, H. Von Ihering, also was often handicapped by 
having too scanty material. All previous writers had no clear conception of the 
range of variation in the various forms, and thus their descriptions generally are 
those of individuals, often indeed very elaborate and complete, but without proper 
emphasis laid upon the really important specific characters. Simpson’s “ Descrip- 
tive Catalogue” (1914) did not much improve matters, since he was largely de- 
pendent upon the unsatisfactory publications of previous authors. 

I do not claim, by any means, that my treatment of these shells overcomes all 
these difficulties; on the contrary, I am in many particulars not at all satisfied 
with the results obtained. Nevertheless, I claim that the study of the soft parts 
of a great many forms has furnished a basis for the proper understanding of what 
the “species” are, and has, at least, furnished a clue to their systematic arrange- 
ment, incomplete and fragmentary, it may be, but which probably will prove to 
be of great value, when the soft parts of all or most of the species are known. 

The difficulty encountered in recognizing the described forms is sometimes 
exasperating. We should expect, in cases where exact type-localities are given, 
and where material from these is at hand, that it would not be very great. But, 
for instance, even of the species described by Von Ihering from Sao Paulo, I have 
recognized only a comparatively small number, although I possess a large quantity 
of material representing the Naiades from that state. In other cases, when the 
type-locality is vaguely, or not at all, given, it has been practically impossible to 


ORTMANN: SOUTH AMERICAN NAIADES. 453 


be sure of the identification. In consequence I have been compelled to introduce a 
number of “new species,” although I am afraid that some of them are not really 
“new.” But I must leave the task of making out their synonymy to others, who 
have access to authentic material representing the older forms. It should also 
be remembered that the introduction of new names is justified by the rules of 
nomenclature, when an original description is insufficient to enable the species to 
be recognized. 


GENERAL REMARKS AS TO THE AFFINITIES AND GEOGRAPHICAL DISTRIBUTION OF 
THE SourH AMERICAN NATADES. 


The earlier writers generally placed the South American forms in the old 
collective genera, Unio and Anodonta, to which a kind of intergrading group, called 
Monocondylea, and certain specialized types, such as Hyria and Castalia, were 
added. Von Ihering was the first to recognize that the South American ‘“ Ano- 
donta,” so-called, differs from the Anodonta of the northern hemisphere in important 
characters, and that it is related to certain African forms, Mutela, Spatha, ete. 
He calls this genus Glabaris Gray = Anodontites Bruguiére. But he left the other 
forms under Unio. For these Simpson (1900) used the name Diplodon Spix. In 
my preliminary report on South American Naiades (Ortmann, 191la, pp. 108, 120, 
129, 130) I was able to show that Diplodon, as well as Hyria and Castalia, differ 
anatomically from the Unionide of the northern hemisphere, and that Von Ihering’s 
separation of Glabaris from Anodonta is fully justified and correct. I also found 
that the genera Hyria, Castalia (= Tetraplodon), and Diplodon, recognized by 
Simpson as a peculiar group, but still placed with the Unionidae, are actually more 
nearly allied to “Glabaris,” and form with this a group, the family Mutelide, which 
should be divided into two subfamilies, the Hyriine and Muteline, each witha 
number of genera, the anatomy of many of which, however, was still unknown. 

Subsequent investigations brought out the fact that Simpson (1900) was cor- 
rect in associating certain Australian Naiades with the South American Diplodon, 
since I was able to show that D. australis has practically the same anatomical 
structure as the South American Diplodon (Ortmann, 1912), but that it should be 
elevated to the rank of a separate genus, Hyridella Swainson, admitted as a sub- 
genus by Simpson. 

The systematic arrangement and geographical distribution of the families and 
subfamilies of the Naiades would thus be as follows: 


454. MEMOIRS OF THE CARNEGIE MUSEUM. 


Superfamily NATADES. 


I. Family MARGARITANIDE......... Eurasia and North America (discontinuous). 

II. Family Unronip: 
1. Subfamily Unioninam.......Eurasia, Africa, North America, southward to Central America. 
2. Subfamily ANODONTIN®”..... Eurasia, North America, southward to Central America. 
3. Subfamily LAMPSILIN® ..... North America southward to Mexico. 

III. Family Mure.ipa: 
1. Subfamily Hyrimam........South America (but not in Central America), Australia. 
2. Subfamily Muretin» ......South America to southern Mexico, Africa. 


I can not improve upon this arrangement at present. It possibly might be 
advisable, in future, to elevate the two South American subfamilies to the rank of 
families, but I refrain from doing this, chiefly because the African and Australian 
forms belonging to them are too poorly known. The fact that in South America 
two groups of Naiades are found, which are more closely allied to each other than 
to any other group, is well expressed by uniting them into one family (Mutelide). 

The more primitive subfamily, Hyriine, is found all over South America, but 
becomes rare in the northern parts (Venezuela and Colombia), and is missing, so 
far as known, in Central America. It is quite abundant in Chile, where the Mu- 
teline are absent, and it is also found in Australia.” 

The more specialized group, subfamily Muteline, is found in South America, 
east of the Andes. It is missing in Chile, but has been reported from the Pacifie 
drainage in Ecuador. It goes into Central America and reaches southern Mexico. 
On the other hand it is represented in Africa, probably all over the continent, 
with the exception of the Mediterranean region. 

This geographical distribution of the larger groups is extremely significant, 
for it serves to support certain theories as to the origin of the South American 
continent, its former connections, and the origin of its fauna. The presence of 
the Hyriine both in South America and Australia indicates the former connection 
of both continents, probably by way of Antarctica, and the fact that species of 
Diplodon, the most primitive of the South American Hyriine, are found in Chile, 
is entirely in keeping with this. The fact that Unionide with certam Hyrine 
structures® are found chiefly in southeastern Asia, suggests that they probably 

2 It is unknown whether all the Australian Naiades belong here. Unionide related to the Hyriine 
in having the septa of the marsupium interrupted, are known to me from southeastern Asia (Siam, 
China) and northwestern America (Pacifie slope), but these forms certainly are Unionide in all other 
respects. . 

‘ Interrupted septa in the marsupium are known in the Asiatie Unionine: Lamellidens (Ortmann, 
191la, p. 106); in Hyriopsis and Contradens (Ortmann, Nautilus, XXX, 1916, pp. 85 and 106); and, 
according to the figures of Haas (System. Conchyl. Cabin., XIX, 1911 and 1912), also in Rectidens and 


Acuticosta. 


ORTMANN: SOUTH AMERICAN NAIADES. 455 


originated on the old connecting land between Asia and Australia (Sino-Australian 
continent) or in Australia, and that Diplodon first reached Chile (in Mesozoic times) 
coming from Australia, and subsequently invaded the Brazilian mass. The 
modern forms of the Hyriinw (Castalia, Hyria) chiefly have their center in the 
basin of the Amazon, a comparatively young part of the continent. 

The more advanced type, represented by the subfamily Muteline, developed 
probably in Brazil at the end of the Mesozoic, when it had a chance to spread 
over the old connection across the Atlantie (Archhelenis of Von Ihering), and the 
immigration of this stock into Central America is of rather late date (late Tertiary). 
It is not very likely that the Muteline reached South America coming from Africa, 
because there is no trace of them found in southern Asia.’ 


Dracnostic CHARACTERS OF THE SourH AMERICAN NAIADEs. 
(See Text-figures 1, 2, 3.) 
. Fo ’ 
Family: MUTELID Ortmann (1911).° 


1. Diaphragm between branchial and cloacal cavity formed anteriorly by the 
gills, posteriorly by a solid union of the mantle margins (Figs. 1, 2, 3, t). (No such 
mantle connection in Unionidae). 

2. Anterior end of inner gill (Figs. 1, 2, 
3, i) broadly attached, and in contact with 
posterior base of palpi (h). (In the Union- 
ide, there is always a longer or shorter space 
between these parts.) 


3. Anal and branchial openings (a and Fig. 1. Diagram of soft parts of female 


b) sharply separated from each other by the of Diplodon trifidus (Lea). Natural size, 
union of the mantle margins (See Character left section of mantle removed. a Anal 
1 1 i | 1 al but opening; 6, Branchial opening; h, Palpi; 7, 
Je anal opening Open or Closed above, Dut Inner gill; 0, Outer gill; p, Pes: s, Closed 


there never is a supra-anal opening. (In the part of anal opening; ¢, Union of mantle 
Unionidae, the anal may be open, but, when _ separating anal and branchial openings. 
closed, there is always a supra-anal opening.) 


4Tn Africa there are also Unionide of the subfamily Unionine; they undoubtedly point to a con- 
nection with Asia, since such forms are plentiful there, and this indicates a different route of immigra- 
tion from that of the Muteline. 

° The name depends upon the investigation of the anatomy of the African genus Mutela, which is 
unknown, but we have every reason to assume, chiefly through Von Ihering’s study of the shell, that 
this genus will fall under this family. The family name Mutelid@ was first used by H. & A. Adams 
(1858), but for an entirely different association of forms. The Mutelide of Simpson (1900) correspond 
to our Muteline. 


456 MEMOIRS OF THE CARNEGIE MUSEUM. 


4. Gills with or without water-tubes, and with isolated, scattered inter- 
laminar connections, or with interrupted or solid septa. (In the Unionidae, mostly 
uninterrupted septa and water-tubes are found; very rarely are they interrupted; 
the forms with the latter probably form the connection with the Mutelide.) 

5. Marsupium only in the inner gill (Figs. 1, 2, 3, i). (In the Unionidae, the 
marsupium is either in all four gills, or in the outer gills, never in the inner gills 
alone.) 

6. Certain advanced genera of the Mutelide show a tendency to close the 
branchial opening in front by a mantle connection. (Such a connection is entirely 
unknown in the Unionidae.) 

The foregoing are the anatomical characters. The shape of the shell and its 
parts are subject to so many variations, both in the Mutelide and the Unionide, 
that it is practically impossible to point out general differentiating characters. 
Different and often very peculiar types of shell, occurring independently, are fre- 
quently observed, so that it is clear that the shells by responding to certain stimuli 
and requirements have acquired sim- 
ilar shapes in forms, which belong to 
different families (convergency or 
parallelism). Simpson (1900 and 
1914) found it impossible to give 
shell-characters for his subfamily 
“ Hyriane”’ = Hyriine+certain Uni- 
onine, except beak-sculpture, and he 
was mistaken in this. In our arrange- 
ment, this is the only character, 
which might be mentioned, but not 


without qualification. We may ex- 


MG. 2 iagram es arts omi f : . 
Fig. 2. Diagram of the soft parts of female of press it thus: The Mutelide have ra- 


Caslalina nehringi Von Ihering. Natural Size, left . 5 3 
dial beak-sculpture, if such is present 


section of mantle removed. (Lettering as in Text- 
figure 1, p. 455.) at all);° while the Unionide rarely 
have distinct radial beak-sculpture, 
‘but commonly other types, zig-zag, double-looped, or concentric. 
Some Mutelide have, indeed, shells which completely mimic those of certain 
Unionide. Species of Diplodon often externally So much resemble certain species 
® But even this should be qualified. In certain species of Anodontites in the subfamily Muteline 
I have observed something like concentric beak-sculpture, while, as a rule, the Muteline have no beak- 
sculpture whatever. 


ORTMANN: SOUTH AMERICAN NAIADES. 457 


of the North American Elliptio, that without a minute examination of muscular 
impressions, hinge-teeth, etc., it is impossible to recognize them, when the locality 
is unknown. The only reliable character in this case, beak-sculpture, is often 
obliterated by erosion. Species of Anodontites often look like species of Anodonta. 
Here the examination of beak-sculpture, muscular impressions, and the ligamentinal 
sinus establishes their affinity. On the other hand, there are Mutelide which are 
easily recognized by the peculiar shape of the shell, and could never be confounded 
with Unionide (Castalia, H yria, Mycetopoda, ete.). 
The characters of the two subfamilies of the Mutelide are the following: 


Subfamily Hyruna: Ortmann (1911). 


Hyriane Swarnson (1840), very cloself corresponds to this. Lamphoramphus- 

group of Hyrianew Simpson (1900). 

1. Anal opening (Figs. 1, 2, a) closed above (s), slit-like (in South American 
forms), or forming a short, tubular siphon (Australian forms). 

2. Marsupium generally an interrupted network of interlaminar connections 
(Figs. 1, 2, 1), the connections often standing in rows, thus forming incomplete 
septa and incomplete, communicating, water-tubes. In rare cases, the inter- 
laminar connections of the marsupium (but not of the non-marsupial gills) form 
solid septa and isolated water-tubes. Marsupial part of gill often restricted to 
only a section of it. 

3. Non-marsupial gills always with poorly developed, scattered interlaminar 
connections. (Figs. 1, 2, 0.) 

4, Inner lamina of inner gills always entirely connected with abdominal sac. 

5. Palpi (Figs. 1, 2, h) subtriangular or subfalciform, with gently curved lower 
margins, and somewhat produced posterior points. 

6. Larva a glochidium (See Fig. 4, p. 469). 

As a character of the shell may be mentioned the beak-sculpture, which is 
generally present (often poorly developed, rarely absent), and always radial. 
The hinge-teeth are always present, and generally well-developed. Dorsal muscle- 
scars are present. 

Subfamily Mure.ina Ortmann (1911). 


Mutelide ApaAms (1858), Stmpson (1900). The name depends, of course, on the 
genus Mutela, the anatomy of the soft parts of which, as has been pointed out 
already, remains to be investigated. 

1. Anal opening (Fig. 3, a) open (in South American forms, except Myceto- 
poda) or closed above (in African forms and Mycetopoda), slit-like. 


458 MEMOIRS OF THE CARNEGIE MUSEUM. 


2. Marsupium (Fig. 3, 7) with well-developed, continuous septa, forming well- 
defined, isolated water-tubes, with a peculiar longitudinal ridge or swelling on the 
septa near the outer lamina of the gill (Pl. XLVIII, figs. 6, 8). When gravid, 
only the inner compartment of the water-tubes (towards the inner lamina) is some- 
what extended and filled with eggs; the outer compartment becomes a secondary 
water-tube (Pl. XLVITI, fig. 7b). 

3. Non-marsupial gills (Fig. 3, 0) also with septa and water-tubes, but the 
septa less strongly developed and without a ridge. 

4. Inner lamina of inner gills entirely 
connected with abdominal sac (South Ameri- 
can forms), or free from it (African forms). 

5. Palpi nearly semicircular, longer than 
high, with a short posterior truncation, 
strongly curved lower margins, and indis- 
tinct posterior points (Fig. 3, h). 

6. Larva supposed to be a lasidium 


tts _ (aecording to Von Ihering). 

Fic. 3. Diagram of soft parts of female of 
Anodontites patagonica rubicunda (Lea). Nat- The shell generally has no beak-seulp- 
ural size, left section of mantle removed. a, ture whatever. In very rare cases a trace 
Anal opening; b, Branchial opening; h, Palpi; of eoneentric sculpture has been observed 


i, Inner gill; 0, Outer gill; p, Pes; t, Union of (see ynder Anodontites trapezea). Hinge- 


mantle separating anal and branchial openings. seethnaroncomless Gbeolese! Keduecd tennis 
ber, or size, and very often entirely absent (Anodontine type of hinge). Dorsal 
muscle-scars mostly absent in South American forms, very rarely a faint trace 
seen, or a few are present, as in Leila. In African forms, there is one single well- 


developed dorsal muscle-scar. 


Subfamily HYRIIN 42 Ortmann. 
GENERAL REMARKS. 


Shell of various shapes, subelliptical, subtrapezoidal, subovate, suborbicular, 
or subtriangular, sometimes more or less alate. Beak-sculpture mostly present, 
rarely missing, but often indistinct or obliterated by erosion, always of the radial 
type, with two sets of radial ridges, starting from two points, immediately in front 
and immediately behind the tip of the umbo, and extending to a varying degree 
upon the disk. The posterior ridges of the anterior set, and the anterior ridges of 
the posterior set, generally interfere with each other in the middle of the disk, 


= 


ORTMANN: SOUTH AMERICAN NAIADES. 459 


coming there into contact in a sharp angle. There are sometimes irregularities 
in the beak-sculpture obscuring their radial character. 

Hinge-teeth always present, but rather variable in number, size, and shape. 
Normally, there are, as in most other Naiades, two laterals in the left valve, and 
one lateral in the right valve, but individual variations may occur in this respect. 
The pseudo-cardinals are much more variable. Originally their arrangement 
seems to be similar to that found in primitive Unionidae: that is to say, there are 
two in the left valve, and one or three in the right; of the latter, the middle one 
may be the main tooth, fitting in between the two teeth of the left valve, and the 
anterior and posterior tooth may be accessory. However, this arrangement is 
very often changed by the suppression of certain teeth, and the addition of others. 
The most general condition is when of the two pseudocardinals of the left valve 
the posterior is more or less obsolete, and often entirely wanting, and only the 
two anterior teeth of the right valve are present. Thus the left valve appears 
to have only one pseudocardinal (Aspidon of Von Ihering) and two laterals, and 
the right valve has two pseudoecardinals (Dexion and Epidexion), and one lateral. 
This is chiefly the case in certain species of Diplodon, where the pseudocardinals 
are greatly compressed, and directed more or less parallel to the hinge-line, and 
this should be kept in mind for the distinction of those species of Diplodon, which 
resemble in shape certain North American species of Elliptio, where the normal 
arrangement shows two pseudocardinals in the left, and one in the right valve. 

This isnot the only variation. Additional teeth may turn up, and chiefly when 
in the left valve anterior to (or above) the anterior pseudocardinal an additional 
tooth is developed (Epaspidon, Von Thering). 

The names Aspidon and Epaspidon, Dexion and Epidexion, may be used to 
advantage; but we should not forget that originally there is in the left valve a 
tooth behind the Aspidon (regarded by Von Ihering as being accessory), and that 
there is often in the right valve another (third) posterior tooth, behind the Dexion.’ 

Further, there is much variability in the shape of the teeth. The pseudo- 
cardinals, as has been stated, are often compressed, lamellar, and smooth. But 
often they are more solid, or stumpy, when they are frequently more or less split 
and divided, sometimes almost cut up into a number of teeth. The laterals may 
be smooth or corrugated, the corrugations standing obliquely on the faces; and in 
certain genera there are characteristic regular and parallel striations or ridges 

7 Compare also Odhner, 1918, p. 574 ff. (Homologies of hinge-teeth of “ Unionidae ”). Odhner 


seems to be right in a general way, but the hinge of the Navades is extremely complex and individually 
variable. 


460 MEMOIRS OF THE CARNEGIE MUSEUM. 


standing vertically to the edge of the teeth. Similar ridges may be present on 
the pseudocardinals. 

In the shape of the muscle-sears on the inside of the shell, there exists no 
great difference between the Hyriinw and Muteline. The general rule is in the 
Hyriine that the upper anterior retractor-scar is distinctly separated from the ante- 
rior adductor impression, while the lower anterior retractor-scar is confluent with the 
latter. Very rarely the lower anterior retractor-scar is isolated. (In the Muteline 
either all three sears are confluent, or the lower anterior retractor-scar is isolated; 
the upper anterior retractor-scar is hardly ever isolated). |The posterior muscle-scars 
are confluent, the posterior retractor-sear forming a small process at the upper margin 
of the adductor-sear. The muscle-scars may be deeper or shallower, the upper an- 
terior retractor-sear generally is rounded, small, and remarkably deep. 

Dorsal muscle-sears are present in the Hyrtine (mostly absent in the Muteline) ; 
they are variable in number, generally only a few, and are located in the bottom 
of the shallow beak-cavity, forming an irregular row parallel to the hinge-line, or 
somewhat oblique. In some forms with deep beak-cavities, these scars are situated 
on the inner side of the hinge-plate (behind the pseudocardinals and the inter- 
dentum). 

The line of the mantle-impression is always simple, without a sinus poster- 
iorly. The ligamental sinus lies on the margin of the shell behind the ligament, 
over the posterior part of the lateral teeth (rarely more in front), and is always 
small and shallow (longer than deep). (in the Mutelinew, the ligamental sinus is 
generally much deeper, with a sharp lower point.) 

The characters of the soft parts of the Hyriine have been pointed out above. 


THE GENERA OF THE HyrIIN«&. 

The genera of the Hyriine have been hitherto differentiated according to 
the shape of the shell, the character of the beak-sculpture, and the character and 
the sculpture of the hinge-teeth. According to Simpson (1914 pp. 1194 ff.) there 
are seven of them in South America: Tetraplodon Spix (recte Castalia Lamarck); 
Castalina Von Ihering; Castaliella Simpson; Callonaia Simpson; Hyria Lamarck; 
Prisodon Schumacher; Diplodon Spix. 

In addition, there are species belonging to this group in Australia (and probably 
also in New Zealand), which have been placed by Simpson in Diplodon, but have 
been separated by him under the subgenus Hyridella Swainson. I have shown 
(Ortmann, 1912) that the type of Hyridella (Unio australis Lamarck) actually is 
closely allied to Diplodon, but that probably it is better to regard Hyridella as a 
genus by itself. 


ORTMANN: SOUTH AMERICAN NAIADES. 461 
The differences of the South American genera may be tabulated as follows: 


a. Shell not alate, or only very slightlyalate behind, subelliptical, subovate, subrotund, or subtriangular. 
b. Shell subelliptical, subovate, or subrotund, but not subtriangular. Beaks not much elevated, 
with radial beak-seulpture, variously developed. Posterior ridge absent or poorly developed; 
when present and distinet, the shell is elongated. Hinge teeth more or less smooth or dis- 
sected, or corrugated, but without vertical parallel ridges. Interdentum very narrow. 
Diplodon. 
6b. Shell subtriangular (or subquadrate). Beaks more or less elevated and with rather deep beak- 
cavities. With or without beak-sculpture. Posterior ridge well developed, defining a 
distinct posterior slope. Hinge-teeth generally much dissected, and often with parallel 
vertical ridges. Interdentum well developed, rather broad. 
c. Sides of shell somewhat flattened, posterior ridge moderate, posterior slope elevated in the 
middle and slightly alate (thus the shell becomes subalate). Hinge-teeth smooth, erenu- 
iigeiel rove yaa ompeyence lel Mate eee bain cit cece Sein ae ean ae ere CUI (108 
ce. Sides of shell more or less convex, posterior ridge sharp, posterior slope truncated, not 
elevated (or only so in the young). Hinge-teeth with parallel ridges. 
d. Radial beak-seulpture present. 
e. Beak-seulpture strongly developed, extending over a large part of the disk. Surface 
MommCONCenthicalliy sul cAbeC sam ere patel u- ts ciierieie «cho eye versus 8 oe waists Castalia. 


ee. Beak-seulpture short anteriorly, extending farther on the disk posteriorly. Surface 


covered with strong, even, concentric ridges (suleated).............Castaliella. 
dd. Beaks without distinct sculpture, and surface of shell smooth.............Callonaia. 
aa. Shell subrhomboidal or subtriangular, strongly alate behind, slightly alate in front. 
b. Beaks with strong radial sculpture. Posterior ridge moderately developed.............Hyria. 
bb. Beaks without sculpture. Posterior ridge strongly developed, sharp and high... ... . . Prisodon. 


From the expressions used in distinguishing these genera, it appears that 
Diplodon is a rather composite genus, containing shells of various, more or less 
indifferent types, while the other genera represent more marked and _ peculiar 
shapes, with Castalina forming, to a degree, a connection between Diplodon and 
the rest. This indicates that Diplodon includes the more primitive and generalized 
forms of the subfamily, while the others are more specialized and advanced. In 
a general way, this is supported by the investigation of the anatomy. However, 
it is much to be regretted that I am unable to give any information as to the struc- 
ture of the soft parts of the genera Castaliella and Callonaia. The former is en- 
tirely unknown to me, and of the latter I possess only two odd valves. Also of 
Prisodon I only have the soft parts of a young individual. Better material is at 
hand to represent the other genera. 

Generally speaking, the anatomy of all these forms is rather uniform; yet 
there are certain characters in which they differ, and some of these, indeed, indi- 
cate a gradual advance in the structure. 


462 MEMOIRS OF THE CARNEGIE MUSEUM. 


One of these characters has been noticed long ago, and has been discussed in 
detail by Von Ihering. This is the tendency manifested in certain forms to close 
the branchial opening in front by a connection of the mantle-margins, which is 
a character entirely wanting in the Unionidae, but it is found occasionally in both 
subfamilies of the Mutelide (Hyriine and Muteline). But numerous members 
of this family do not have this character, and thus it is evident that the absence 
of this mantle-connection indicates a primitive condition, while its presence is a 
more advanced stage, expressing the tendency to transform the branchial opening 
into a closed tube (siphon). 

According to Von Ihering (1898), the mantle-connection closing the branchial 
opening anteriorly is always present in Castalia. I have been able to confirm 
this only partially. Of typical species of Castalia I possess the soft parts of six 
specimens of C. acuticosta: they show the branchial opening closed with one ex- 
ception, where it is open. In C. wndosa, a somewhat aberrant type, Von Ihering 
describes the branchial as normally closed, but he says that in four out of twenty- 
one specimens examined the mantle-connection was missing.* Of this species I 
have five specimens with soft parts, of which three have the branchial closed, while 
it is open in two of them. In one of the latter, however, a small one, it may be 
torn. It must be admitted that also in other cases this connection of the mantle 
may have been torn in life or in preservation.’ And thus it might be that normally 
this mantle-connection is present in Castalia. 

Castalina, according to Von Ihering, varies in the development of this character 
in the different species and individuals. He has investigated two males of C. 
nehringi, and one had the branchial closed, the other open. In eight females ex- 
amined by myself, I found the branchial open. In C. martensi Von Ihering found 
the branchial opening in most cases closed. I have no soft parts of this species. 
But in two specimens of C. psammoica, which I possess, one has this opening dis- 
tinetly closed in front, in the other this is not the case. 

Nowhere else within this subfamily has this character been found. Castaliella 
and Callonaia may possess it, but their anatomy isunknown. Of Hyria and Prisodon 


8 In Von Ihering’s description (1893, p. 86) there is a very singular mistake. He speaks of the 


“cc ? 


mantle-connection ‘ Bruecke ” between the two “ siphons,’ while he undoubtedly means the con- 


’ 


nection in front of the branchial ‘ siphon.’ This is the one which is sometimes missing. The absence 
of the connection between the anal and branehial openings would be something unheard of; in fact, 
has never been observed by me in any member of the family. 

® We must recall that similar variations or mutilations with regard to the mantle-connection which 
separates anal and supra-anal openings in the Unionid@ are well established, for instance in the genus 


Fusconaia. 


ORTMANN: SOUTH AMERICAN NAIADES. 463 


it is positively known that no such mantle-connection exists, and the same is the 
case in all investigated species of Diplodon. 

Thus it is seen that Castalina and Castalia (and possibly also Castaliella and 
Callonaia) form a group within the subfamily, which is not only specialized in the 
shape of the shell, but also in the tendency to close the branchial opening an- 
teriorly. As Castalina forms a transition from Diplodon to Castalia in the shell, 
so it is transitional also in this latter character, and thus it is perfectly clear that 
Castalina and Castalia cannot be primitive types, and other peculiar characters, 
which they possess, probably also should not be regarded as primitive. 

This is especially true of the parallel ridges vertical to the edge of the lateral 
hinge-teeth (also sometimes present on the pseudocardinals). This character is 
best developed in Castalia (Plate XX XIX, figs. 8c, 8d), but Castaliella is also de- 
scribed as showing traces of it, and Callonaia has it. But here again Castalina 
is transitional toward Diplodon. Castalina nehringi has, according to Von Ihering, 
hinge-teeth obliquely corrugated, but never with parallel ridges vertical to the 
edge. This is quite correct, as far as concerns the laterals; but some of my 
specimens show that the furrows of the cardinal teeth occasionally may be nearly 
parallel, thus producing nearly parallel ridges. In Castalina martensi vertical 
ridges are present and well-developed, at least in the anterior section of the lateral 
teeth, but young specimens do not show them. My specimens of Castalina psam- 
moica have the vertical ridges poorly, or not at all, developed. 

This sculpture of vertical ridges upon the hinge-teeth in Castalia and the 
allied genera has been much discussed in the literature. It is well known that 
Neumayr believed that these ridges are homologous to similar structures seen 
in the Trigoniidae, and that Castalia should be directly connected with Trigonia, 
and this idea has been taken up by other authors. However, Von Ihering (1893 
p. 85) has pointed out that this is incorrect. From the above considerations we 
now know, that there undoubtedly is a genetic series, which leads from Diplodon 
through Castalina to Castalia, with the beginning at Diplodon, and the end at 
Castalia; and, consequently, the vertical ridges on the hinge-teeth in Castalia are 
not an ancestral character, inherited from Trigonia, but are a new acquisition, 
marking an independent, comparatively high development of the Naiad-hinge."° 

Hyria and Prisodon may, or may not, possess these vertical ridges on the hinge- 
teeth. If present (Prisodon alatus, Pl. XL, figs. 2c, 2d), they are seen chiefly in 

10 This idea has also been suggested by Pompeckj (Gegen Steinmann’s Geologische Grundlagen der 
Abstammungslehre, im 3ten Jahr.-Ber. Niederswchs. Geol. Ver., 1910, p. 12) in eriticizing Steinmann’s 
attempt at a polyphyletie derivation of the Naiades from various Trigoniide, Odhner (1918, p. 577, 


footnote) also considers the sculpture of the teeth in Castalia as a secondarily developed character. 


464 MEMOIRS OF THE CARNEGIE MUSEUM. 


old specimens, while they are lacking in the younger ones, but old specimens also 
may not show them. Thus these two genera should be compared in this respect 
with Castalina, and it is quite possible that they have here their roots, the shape 
of the shell of Castalina also indicating in its elevated posterior slope the ‘‘alate”’ 
shape of Hyria. 

Thus we see that the genera Castalina, Castalia, and probably also Castaliella 
and Callonaia, form a series descended from Diplodon, characterized by peculiar 
tendencies in the shell and in the soft parts. The shell tends to assume a more 
or less triangular shape, with high beaks, with a strong posterior ridge, and a trun- 
cated posterior slope. The hinge-teeth tend to develop vertical ridges, and the 
interdentum becomes wider. The soft parts tend to close the branchial opening 
in front. All the rest of the soft parts, however, remain here in a comparatively 
primitive state, being identical with, or standing very close to, the most primitive 
type of Diplodon in the interrupted character of the septa of the gills (See below). 
It also should be mentioned that the glochidia of these forms, where known, as in 
Castalina and Castalia, possess the same shape and the peculiar hooks observed in 
many species of Diplodon, but not in all (See below). 

Apparently a side-branch of this series is formed by Hyria and Prisodon. 
Here the “‘alate’’ character of the shell, slightly indicated in Castalina, is empha- 
sized, and developed to an extreme degree; the hinge-teeth have a slight tendency 
to develop vertical ridges, exactly as in Castalina: but in the anatomy these forms 
do not show the tendency to close the branchial opening in front. Also in the 
rest of the soft parts they remain upon the primitive Diplodon-stage. 

We may express the affinities as follows: 


Callonaia Castaliella Prisodon 
Castalia Hyria 
Castalin 
Diplodon 


The genus Diplodon yet remains to be discussed. We have referred to it 
above as the most primitive type within the subfamily, and there are undoubtedly 
a number of species contained in it which have a primitive structure. But there 
are others which differ from them. The first question, however, to be considered 
is which characters we should regard as primitive. 

As far as the shell is concerned, there is considerable variety within this genus. 


ORTMANN: SOUTH AMERICAN NATIADES. 465 


Most of the species are subelliptical or subovate, and moderately elongated; but 
others approach more or less the suborbicular shape. For the latter, Simpson 
has introduced the subgenus Cyclomya, and it is true that these form a rather well- 
defined group, although there are certain species which seem to be intermediate. 

The subquadrate or subtrigonal shape of the Castalia-group is unknown in 
Diplodon, and the well-defined posterior ridge characteristic of this group is very 
rarely found; the species, which have it, are always rather elongated (not trigonal), 
so there cannot be any mistake about them. 

The hinge-teeth are also variable, but generally represent, or are easily com- 
pared with, the normal type described above (p. 459). There are one or two 
pseudocardinals and two laterals in the left valve, and two pseudocardinals and 
one lateral in the right valve. The pseudocardinals may be stumpy, or more or 
less compressed. They, as well as the laterals, may be smooth, or have corruga- 
tions, or may be split and dissected. They never have parallel ridges. 

The beak-seulpture also varies a good deal. It is always radial, but the 
ridges composing it may be shorter or longer, finer or heavier, smooth, or dissected 
by growth-lines, granular, and sometimes they may be irregular. 

But all of these characters of the shell are connected with each other by nu- 
merous transitions, and it is impossible to say that any one type is more primitive 
than another. It is also extremely difficult to arrange the species of Diplodon into 
groups according to these features. Simpson (1914 pp. 1225, 1228) has divided the 
genus into subgenera and subordinate groups, and has attempted to condense the 
results in the shape of a “key,” but this key is practically worthless, of which fact 
anyone may convince himself, when he tries to use it for the identification of a 
species. 

However, when I studied the soft parts of the various-species at my disposal, 
I discovered that there are rather well-marked and apparently important c/raracters 
shown by the anatomy, especially by the structure of the marsupial part of the inner 
gill of the female, while the rest of the anatomy is the same in all species. 

The interlaminar connections of the gills are extremely weak in the male of 
Diplodon, and in the outer gill of the female (which has the same structure as in 
the male). They correspond to the description given by me for Hyria and Castalia 
(Tetraplodon) (Ortmann, 1911a, pp. 115, 117). (See the figures of gills of various 
species on Plates XLV, XLVI, XLVI; also sections of the gills on Plates XLVIT 
and XLVIII). These interlaminar connections are few and scattered over the 
face of the gill, and do not form distinct septa (thus resembling the condition seen 
in the Margaritanide). But in the marsupial part of the inner gill of the female, 


466 MEMOIRS OF THE CARNEGIE MUSEUM. 


these connections become more frequent, are heavier, and stand closer together. 
Very often we see short connections grouped together either in a reticulate form, 
or in rows parallel to the gill-filaments, 7e., vertical to the edge of the gill (See text- 
figs. 1 and 27, on pp. 455-6), and it should be noticed that precisely the same ar- 
rangement is also seen in the Australian Hyridella (Ortmann, 1912, pp. 100-103, 
fig. 1). The connections of adjoining vertical rows may alternate in an irregular 
way, and may thus form irregular transverse or oblique rows. Towards the edge of 
the gill, and near the base, the connections are often somewhat elongated, stand 
closer together in the same row, and thus a more distinct arrangement into vertical 
septa is brought about, separating more distinct water-tubes (ovisaes), which, how- 
ever, are laterally connected with each other by the interruptions of the septa 
(See Pl. XLV,.figs. 1b, 2b, 3; Pl. XLVI, figs. 1, 2,3, 4, 6, 7a, 7b; Pl. XLVIL fig. 1). 

There is no doubt that the arrangement described above is primitive, for it 
most closely approaches the condition seen in the male gill. The marsupial strue- 
ture is simply brought about by a more frequent and heavier development of the 
interlaminar connections of the male, which approach each other, and partly ar- 
range themselves in vertical rows. 

A step in advance is observed when the vertical rows prevail over the reticulate 
arrangement, and extend over the whole marsupial portion of the gill. Such cases 
are found, and in them the interlaminar connections may be shorter or longer, 
but they always stand close together in each row, so that we have all through the 
marsupium the appearance of distinet septa, which, however, are perforated by 
holes, so that the water-tubes (ovisacs) communicate with each other; this is most 
evident in Diplodon piceus (Pl. XLVI, fig. 2). 

Furthermore in a few species (D. decipiens, Pl. XLV, fig. 4b, and D. mogymirim, 
Pl. fig. 5c; see also Pl. XLVII, fig. 7, and Pl. XLVIII, figs. 2a, 2b), I have observed 
a further advance in this structure. Here the septa become solid, the interruptions 
are missing, and each septum runs from the base of the gill vertically towards the 
edge, exactly in the manner which we know to be the characteristic condition in the 
Unionide. Well-defined water-tubes, which do not communicate, are thus formed. 
The species, which show this structure, have in the marsupial part of the gill 
hardly any indications of interruptions of the septa. In the non-marsupial por- 
tions, as well as in the outer gill of the female, and both gills of the male, the usual 
structure of Diplodon is present, showing few and scattered connections. This 
reveals that the solid septa of these species of Diplodon represent the highest stage 
in the marsupial development in this genus, and that this feature should not be 
considered as homologous to the septa of the Unionide. It is analogous, and has 
been independently acquired. 


ORTMANN: SOUTH AMERICAN NATADES. 467 


There are other differences in the marsupium of the species of Diplodon, and 
these depend upon its location within the gill. Tn the Australian Hyridella nearly 
the whole inner gill is marsupial, only very small portions at the anterior and 
posterior ends remaining non-marsupial, a very common condition in the Unionide 
where the whole outer gill may be marsupial. In Diplodon we sometimes observe 
a similar arrangement (O. piceus, Plate XLVI, fig. 2), but generally a more con- 
siderable part at the anterior as well as at the posterior end of the gill is non- 
marsupial, so that the marsupium is restricted to the middle portion (about half) 
of the gill. The marsupial part may become still more reduced in size, and may be 
located not in the middle of the gill, but more toward the front, or toward the pos- 
terior end. In either case the posterior or anterior half of the gill is nearly or 
quite non-marsupial. It should be noted that I have observed this shifting of 
the marsupial part only in cases where the marsupial structure is comparatively 
primitive, with the interlaminar connections arranged in a reticulate way or as 
interrupted septa, but never in forms with solid septa, where the marsupial part 
always extends over a large seetion in about the middle of the gill. (Compare 
figures on Pl. XLV, XLVI, XLVII.) 

All these differences described in the structure and location of the marsupium 
are constant within the species. In some forms, indeed, my material is rather scanty ; 
but in quite a number of other cases I have a sufficient number of individuals 
with soft parts, and I have invariably found that all females of the same form and 
from the same locality agree with each other, with the only qualification that in 
young females the marsupium is generally less extended, and occupies a smaller 
section of the gill (Compare Pl. XLVI, figs. 5b and 5c; Pl. XLVI, figs. 7a and 7b). 

It should be emphasized that these marsupial differentiations are only found 
within the genus Diplodon. The other genera of which I have anatomical material 
stand generally upon the stages which I have described as the more primitive in 
Diplodon. Firstly the structure of the marsupium is of the reticulate type in 
the middle, with more or less development of interrupted septa towards the edges 
of the gill in Hyria (Ortmann, 1911a, p. 115) and Castalia undosa (ibid., p. 117), 
while in Castalina nehringi the structure showing perforated septa prevails. Cas- 
talia acuticosta seems to agree with C. wndosa, but my material consists of only two 
gravid, rather young specimens, in which the structure cannot be clearly seen on 
aceount of the mass of glochidia filling the marsupium. Secondly the location of 
the marsupium in Hyria and Castalia is in the middle of the gill (one-fourth at 
anterior end, less than that at posterior end, non-marsupial). In Castalina nehringi 
(Plate XLVII, fig. 2) the marsupium has moved a little more backward with about 


468 MEMOIRS OF THE CARNEGIE MUSEUM. 


the anterior half of the gill, and less than one-fourth of the posterior end non- 
marsupial. 

Thus it is clear, that, while the Castalia-Hyria-group of genera in the shape of 
the shell and the hinge-teeth, and the Castalia-group in the conformation of the 
branchial openings represent a higher specialisation, in the rest of their anatomy, 
and chiefly in their marsupial characters, they all remain very close to the primitive 
Diplodon-type. 


THE GLOCHIDIA. 
(See Text-figure 4.) 


In conclusion I may say that I have found differences in the glochidia within 
the genus Diplodon. That certain South American species of ‘‘ Unio” have glochidia, 
was first announced by Lea in the case of U. peculiaris and U. firmus (Lea, Obs., XIT, 
1869, Pl. 34, figs. 80, 82; first published in 1868). He describes and figures them as 
subtriangular in outline, oblique, or upright, the ventral margin with a point, and in 
the text he says that they are “furnished with hooks.’’ However, he neither 
describes nor figures these hooks. 

Von Thering (1893, p. 47) states that hooks are missing in all of the South 
American species examined by him, but that the larvee are true glochidia. 

This is about all we have known hitherto about the larval form of the South 
American ‘‘Unios” = Hyrtinw. I have now found that the normal shape (out- 
line) of the glochidia of Diplodon, and of the subfamily Hyriina, is as described by 
Lea, namely subtriangular, with a point on the lower margin (see fig. 4). In addi- 
tion, I have found that some species actually possess a “hook; but this hook is 
entirely different from the one so well known in the European genus Unio and in 
the Anodontine of Eurasia and North America. The very fact that Lea mentions 
the hook in a kind of perfunctory way, not calling attention to its peculiar features, 
suggests that he never saw the real hook, and that he simply took the point of the 
lower margin of the glochidium for it. 

This Hyriine hook (Fig. 4, b, c, d, e, f, h, k, l, m) differs entirely from the Ano- 
dontine hook. The latter is triangular, attached by a broad base to the point of 
the lower margin, and carries upon its upper surface a number of fine spimules. 
The Hyriine hook is long and narrow, spiniform, with very narrow base, articulated 
to the point of the lower margin, and without any spinules on the upper face, and 
furthermore has a peculiar S-shaped curve. 

It is perfectly clear that this hook is different from that found in the genus 
Unio and the Anodontine. Functionally it may serve the same purpose, that of 


ORTMANN: SOUTH AMERICAN NAIADES. 469 


forming attachment to fishes, but we have not the slightest direct evidence of this, 
and Von Thering directly questions it (J. ¢., p. 47). Morphologically this organ has 
been independently developed. It is analogous to the Anodontine hook, but not 
homologous. 


Fie. 4. Glochidia of Hyriine, enlarged fifty times (drawn from photographs). 
Diplodon hasemani Ortmann (Rio Guaporé), from specimen No. 6. Cat. No. 61.5857. 
D. imitator Ortmann (Santa Maria), from specimen No. 22. Cat. No. 61.9248. 

D. simillimus Ortmann (Morretes), from specimen No. 2. Cat. No. 61.9250. 


Seo OS 


D. vicarius Ortmann (Aqua Quente), from specimen No. 9. Cat. No. 61.9251 (shell of this specimen 
figured on Plate XXXVI, fig. 2). 


e. D. decipiens Ortmann (Serrinha), from specimen No. 10. Cat. No. 61.9253. 

f. D. paulista (Von Ihering) (Mogy Mirim), from specimen No. 10. Cat. No. 61.9256. 
g. D. charruanus (D’Orbigny) (Santa Isabel), from specimen No. 5. Cat. No. 61.5861. 
h. D. piceus (Lea) (Uruguayana), from specimen No. J. Cat. No. 61.5862. 

i. D. hilde Ortmann (Cachoeira), from specimen No. ec. Cat. No. 61.5864. 

k. D. mogymirim Ortmann (Mogy Mirim), from specimen No. 48. Cat. No. 61.9260. 


l. Castalina nehringi Von Ihering (Salto das Cruzes), from specimen No. 1. Cat. No. 61.5119. 
m. Castalia acuticosta Hupé (Rio Guaporé), from specimen No. 1. Cat. No. 61.5112. 


I haye said that only some Hyriinew have this hook. I found it in the case of 
several species of Diplodon, in Castalina nehringi, and Castalia acuticosta, and it 


470 MEMOIRS OF THE CARNEGIE MUSEUM. 


should be mentioned at this point that these hooks appear only in the fully developed 
glochidium, while in younger, immature glochidia they are lacking. 

But it seems that in certain species of Diplodon the hooks are always absent, 
and in these cases the glochidia fully resemble the figures given by Lea. Of course, 
in certain cases it is hard to decide whether the glochidia are fully developed, or 
whether the absence of hooks may be due to the immature condition of the indi- 
vidual. However, I have a case in which I believe I am justified in thinking that 
the glochidia, when fully developed, have no hooks. In three gravid females of 
D. charruanus, the glochidia were all alike, and no hooks were observed (Fig. 49). 
One of these apparently was discharging, and thus we should expect mature glochi- 
dia (unless this were a case of premature discharge). 

In a few other cases I am sure that mature glochidia have no hooks, since 
they are surrounded around the whole lower edge, with a margin, which possibly 
represents the first beginning of the permanent shell of the adult (Fig. 4a, 7). In 
other groups of Naiades, with one exception (Anodonta imbecillis Say of North 
America), nothing of the kind is known in glochidia, as long as they remain within 
the marsupium, and also in these South American forms, when immature, the 
glochidia do not possess this margin. I never have seen a trace of hooks here. 
The margin has much the appearance of that formed in young North American 
Unionide, after the parasitic stage on fish. 

That in these cases the shell should appear at so early a stage, when the larva 
is still within the marsupium of the mother, is indeed remarkable, and possibly 
points to the conclusion that the modes and conditions of embryonic develop- 
ment in the Hyriine differ considerably from those of the Unionidae. 

If the above observations are correct, we would have three types of glochidia 
in the genus Diplodon: (1) Of triangular shape, with hooks; (2) Of the same shape, 
without hooks; (3) Of the same shape, and without hooks, but with a margin around 
the lower edge, which obliterates the triangular shape. 

Whether the second group is real, or only due to incomplete observation, or 
passes finally into the third, remains to be seen. At any rate, it is very desirable 
that close attention should be directed to this question in future work on South 
American Naiades. 

The size of the glochidia is comparatively large, varying from 0.20 to 0.85 mm., 
which might be called a good medium size in comparison with the glochidia of the 
Unionide. 

I regret that my observations on the glochidia of the Hyrvine are not more 
satisfactory. There are indications of important differences, but for the present 


- 


ORTMANN: SOUTH AMERICAN NAIADES. 471 


we must be satisfied with having pointed out this fact, and with hinting that per- 
haps further knowledge of the glochidia may furnish at least some criteria for a 
classification of the species of Diplodon. The same remark holds good of the mar- 
supial structure. In reference to this we possess a little more knowledge, but it 
is still too scanty to make an attempt to use it for classification. The genera with 
the specialized shells of the Castalia- and Hyria-groups are well defined, but their 
anatomy and their glochidia do not present any remarkable differentiations, except 
the structure of the branchial opening in the Castalia-group. On the other hand, 
it appears that the genus Diplodon may finally prove to be composed of an aggrega- 
tion of more varied forms than heretofore supposed, and that the distinctive char- 
acters of these are found chiefly in the marsupium and the glochidium. 

We may perhaps distinguish within the old genus Diplodon a type, which we 
might regard as having the more primitive features, such as a marsupium com- 
posed of interrupted or reticulated septa, occupying the whole or nearly the whole 
of the inner gill, and probably one of the types of glochidia above described. But 
it is hard to say, which form this is. I am inclined to regard the hooked glochidium 
as the more primitive form. The margined glochidium certainly represents a 
more advanced type. It might finally be possible to split up this genus into smaller 
genera, one of which should contain these primitive forms, the others to include 
forms more advanced in regard to their marsupial structure and glochidia. But 
in the present state of our knowledge this step cannot be taken, and we must be 


satisfied with an arrangement of the species based upon the characters of the 
shells. 


THE SPECIES OF THE Hyritn. 
Genus DreLopon Spix (1827). 


Diplodon Srrx, 1827, p. 33 and plate 26.—DreLopon Simpson, 1900, p. 872; 1914, 
p. 1224.4 
Type of genus:—Diplodon ellipticum (ellypticum err. typogr.) Sprx, 1827, PI. 
26, figs. 1, 2. (Same type given by Simpson, 1900.) 


THE SUBDIVISIONS OF THE GENUS DIPLODON. 


Simpson (1914, p. 1225) has made an attempt to divide this genus into sub- 
genera and groups. But he also included in it Australian species under the sub- 
genus Hyridella Swainson, which we now regard as a separate genus, and an African 


1 Diplodon, as accepted by H. & A. Adams (1858, p. 497) as a subgenus of Unio, is an entirely 


heterogenous association of species, including forms from all over the world. 


472 MEMOIRS OF THE CARNEGIE MUSEUM. 


form (Subgenus Levirostris Simpson), which we may with considerable confidence 
assume does not belong here, until the contrary has been positively demonstrated. 

Thus restricted, the genus Diplodon from our point of view falls in Simpson’s 
arrangement into two subgenera, Diplodon (Simpson, 1914, p. 1226) and Cyclomya 
(Simpson, 1914, p. 1278), each subdivided into groups. The characters of the 
shells of these groups run into each other very insensibly, and are found in various 
combinations. The subgenus Cyclomya is somewhat better defined, inasmuch as 
the rounded outlines of the species assigned to it contrast rather markedly with 
most of the elliptical, somewhat elongated shells, assigned by Simpson to typical 
Diplodon. But there are intergrades even here. Typical Cyclomya (of the fune- 
bralis-type) ts irregularly circular, with rounded angles (obscurely pentagonal), 
and has a short and high shell, with the greatest height situated in the middle of the 
shell, at about the middle of the ligament. Simpson included in it as species 
fontainianus, and gratus, which I regard only as higher and shorter forms belonging 
to Diplodon. They have the greatest height of the shell not in the middle, but 
more posteriorly, behind the ligament, and thus their outline is distinetly oblique 
and subtrapezoidal, although approaching the rounded shape. 

Simpson, indeed, says in addition, that the beak-sculpture in typical Diplodon 


b) 


consists of “unbroken ridges,” and that in Cyclomya it is “irregularly radial.” 
In both cases this holds good only for certain species, and cannot be used as a 


generally distinguishing character. 


Subgenus DipLopon Simpson. 
Simpson, 1900, p. 873; 1914, p. 1226. 


Shell more or less elongated; elliptical, ovate, or subtrapezoidal in outline; 
when short, more or less angular and distinctly oblique, with the greatest height 
behind the ligament, but not subcircular with the greatest height under the ligament. 

The arrangement into groups, as here given, does not rest upon that of Simpson. 
It is largely made to suit my material, and does not claim to be final. We may ex- 
press the essential differences in the following key, but with the distinet under- 
standing that there are transitions between the groups, which are hard to place. 


Key Tro Groups IN GeNusS DrIpPLopON. 


a. Shell straight, not oblique, 7.e., the longest axis is nearly parallel to the ligament. 
b. Beak-sculpture covering a considerable part of the disk; ridges, chiefly the posterior, rather 
2th a oe ae Ae OER MA aS Ok rc Gicopoeeas Subs od odo est rs Group of D. hyleus. 
bb. Beak-sculpture more or less developed, rarely covering a considerable part of the disk; ridges 


not very heavy and rather uniform. 


ORTMANN: SOUTH AMERICAN NAIADES. 473 


c. Beak-sculpture well-developed, fine; ridges cut up into fine nodules...Group of D. granosus. 
ce. Beak-sculpture restricted to the region of the beaks; ridges fine, simple, not granular. 


d. Shell rather compressed and flattened upon the sides, subtrapezoidal in outline, and 


not distinctly pointed behind..........------+++++++ssrres: Group of D. chilensis. 
dd. Shell slightly or not at all compressed, convex upon the sides, mostly subelliptical or 


subovate in outline, more or less pointed behind. 
e. Shell rather elongate, not high, subelliptical or subovate. . .Group of D. charruanus. 
ee. Shell shorter and higher, subovate or subtrapezoidal....... Group of D. lacteolus. 
aa. Shell distinetly oblique, with the longest axis forming an angle with the line of the ligament. Outline 


subovate or subtrapezoidal, sometimes rather high and short........----- .Group of D. ellipticus. 


1. Group or Diplodon hyleus. 


Shell subelliptical, subovate, or subtrapezoidal, more or less pointed posteriorly, 
straight, not distinetly higher behind, nor oblique. Beak-sculpture well-developed, 
covering a considerable (but variable) part of the shell; bars rather heavy; those 
upon, and immediately in front of, the indistinct posterior ridge of the shell are 
heavier and longer than the rest; one or two of the median bars joining at their lower 
ends; sometimes the bars are somewhat nodulous (but not granular). 

The beak-sculpture is the most essential feature of this group. Additional, 
but subordinate, characters are found in the hinge-teeth, chiefly the larger ones in 
each valve, which are triangular, rather thick, ragged, but not compressed. Often 
there are two pseudocardinals in the left valve. 

I have seen the female soft parts of two species, D. hasemani and trifidus. 
In both the marsupial part of the inner gill is located in the middle section and 
has interrupted septa. The former species has the margined type of glochidium. 
It seems that this group is not very primitive. 


1. DipLopon nyLaus (D’Orbigny). 
Unio hylwa D’OrBrany, 1835, p. 36; 1843, p. 607, Pl. 69, figs. 8, 9. 
Unio hyleus Sowrrsy, XVI, 1868, Pl. 93, figs. 506 a and 6 (poor figures). 
Margaron (Unio) hyleus Lea (pro parte), Syn. 1870, p. 31. 
Unio hyleus Von Martens, 1894, p. 164. 
Diplodon hyleus Simpson (pro parte), 1900, p. 884; 1914, p. 1274. 

Type-locality.—‘ Rio Palometas, Rio Pari, and Rio Tucabaca, in the provinces 
of Santa Cruz de la Sierra and Chiquitos, in Bolivia.” 

I have been unable to locate the first two rivers; a Rio Tucaraca, in the Chi- 
quitos country (Prov. Santa Cruz de la Sierra in Bolivia), runs to the Paraguay 
River, and I have no doubt that this river was intended, and it is advisable to take 
this as the type-locality. 


474. MEMOIRS OF THE CARNEGIE MUSEUM. 


Other localities.—Von Thering (1893, p. 119) gives this species from Rio Para- 
guay, but also upon D’Orbigny’s authority,” from the Amazon-drainage. Von 
Martens (J. c.) reports it from Paraguay. No other localities have been hitherto 
cited. 

New locality—Rio Paraguay, Sao Luiz de Caceres, Matto Grosso, Brazil, 
(J. D. Haseman coll., May 25, 1909). One specimen. 

Distribution.—The new locality is not very far from the type-locality (Rio 
Tacaraca), about 400 kilometers up the river, and demonstrates that this species 
belongs to the upper Paraguay drainage in Bolivia and western Brazil. According 
to Von Martens it goes down this river to Paraguay. 

D. hyleus and guaranianus have been united by Lea, Sowerby, and Simpson, 
but I think that this is not correct, and that I have both species before me, agree- 
ing well with D’Orbigny’s remarks about them. The real D. hyleus is a larger 
shell, with the lower posterior end somewhat more produced, and with differences 
in the beak-sculpture, which extends over a larger section of the shell, and con- 
sists of rounded bars, which are somewhat irregular, and are rugose or slightly 
nodulous. The figure of D’Orbigny (Fig. 8) shows the sculpture very well. 

I have only a single individual of this species, without soft parts, and have 
drawn the following description from this. 

Description of Shell.—Shell comparatively small, moderately solid, subovate 
or subtrapezoidal, slightly higher behind. Height 64 pr. ct. of length. Dorsal 
margin very gently curved, passing into the posterior margin in a blunt, rounded 
angle. Posterior margin obliquely descending, emarginated, but this emargina- 
tion undoubtedly is an individual feature, since the growth-lines indicate that it was 
not present, when the shell was younger. Lower posterior angle slightly pro- 
duced, but rounded. Lower margin with its lowermost part placed at between 
two-thirds and three-fourths of the length of the shell (from anterior end), curving 
up behind. In the anterior portion it slopes upward in an almost straight line, 
finally curving up into the anterior margin; thus the shell appears slightly narrower 
in front than behind. 

Valves rather flat (in this respect my specimen differs from the original hyleus, 
which is more convex), gently and rather uniformly convex, with the umbonal 
(posterior) ridge weakly marked, and indicated chiefly by a shallow radial de- 
pression upon the posterior slope, which forms the emargination at the posterior 
margin, and makes the posterior ridge appear slightly biangulate towards the 

“ He says that all forms reported by D’Orbigny from Bolivia are from the Amazon-drainage. In 


this particular case this is not correct, since the Rio Tucaraca of Bolivia drains into the Paraguay. 


ORTMANN: SOUTH AMERICAN NAIADES. 475 


posterior end. Diameter of shell 33 pr. ct. of length. Beaks not swollen, and 
not prominent, located at about one-fourth of the length from the anterior end. 

Beak-sculpture strongly developed, covering about half of the disk, the longest 
bars (near the umbonal ridge) are about 20 mm. or more long. There are about 
sixteen or seventeen radial bars, of which the ninth and tenth, and the eighth and 
eleventh, unite in sharp angles, and between the ninth and tenth, there is a short 
odd bar, which is indistinct on account of the erosion of the beaks. Posteriorly the 
bars increase in length as well as thickness: the anterior bars are comparatively 
sharp, narrow, but much injured in my specimen; the posterior bars are broader 
and rounded. Upon the umbonal ridge, the radial bars are again finer, and upon 
the posterior slope there are four or five additional fine bars, which are shorter, 
and restricted to the upper part of the slope. On the lower part of the latter, 
there are a number of fine, irregular, oblique wrinkles. The lower ends of the 
radial bars are cut up, chiefly near the umbonal slope, into irregular, low tubercles, 
and traces of such tubercles may be seen near the lower margin of the shell. 
No distinct lunula is seen in our shell, but this part of the shell is badly eroded. 

Epidermis with numerous, irregular, concentric wrinkles, and traces of radial 
lines. Color brown, much like that of D’Orbigny’s figure. 

Hinge-line gently curved. Ligamental sinus over the posterior fourth (or a 
little more) of the lateral teeth, which are gently curved, one in the right, two 
in the left valve. Pseudocardinals directed obliquely forward and downward, 
two in right valve, the anterior one narrow, low, and compressed, the posterior 
one triangular, cut longitudinally into two parts. In the groove behind this 
tooth, the hinge-line has two small denticles. In the left valve, there are two 
pseudoeardinals, the anterior subtriangular, slightly compressed and simple, fitting 
into the groove between the two teeth of the right valve, the posterior one broader, 
and cut into three parts. Leaving out of sight the comparatively stumpy and 
double character of these teeth, their finer structure can only be regarded as an 
individual characteristic. 

Cavity of shell and beaks shallow. Nacre whitish (discolored in the cavity). 
Anterior adductor-sear distinct, subelliptical; anterior retractor-scar separated 
from it, small, round and deep; anterior protractor-sear connected with the ad- 
ductor-sear. Posterior adductor-scar faint, subovate, with an upper triangular 
process formed by the posterior retractor-scar. Mantle-line faint. Dorsal 
muscle-sears in the cavity of the beaks. 


476 MEMOIRS OF THE CARNEGIE MUSEUM. 


MEASUREMENTS. 


| Length. | Height. | Diameter | Beaks. 
My specimen............|42mm.| 27 mm. =64 pr. ct. of L. | 14 mm. =33 pr. ct. of L. | at 10 mm. =24 pr. ct. of L. 
D’Orbigny’s figure... .... ASiees 25. >) =58 a Ue ES Sa7/ af Se oa 19 ot 
Do., in text ie AO 60 <¢ 40 


Remarks: The chief characters of this species, so far as I am able to make 
them out from the figure and description, and the single specimen at hand, by 
which it differs from the other species of this group, are found in the general shape 
(moderately elongated, slightly wider behind, with rounded posterior angle), 
the beak-sculpture, which covers a rather large portion of the disk, and the rough 
character of the posterior slope. The greater compression of our shell probably 
is individual, and also the emargination of the posterior margin. 


2. DIPpLOoDON GUARANIANUS (D’Orbigny). 


Unio guaraniana D’OrBtGNy, 1835, p. 37; 1843, p. 608, pl. 69, figs. 10-12. 

Type-locality.—Rio Parana, Itaty, Province of Corrientes, Argentina. No 
other locality previously known. 

New Localities—Paraguay River, Corumbi, Matto Grosso, Brazil (H. H. 
Smith coll.). Onespecimen, juv. In swamps of Lambaré, near R. Paraguay, Asun- 
cién, Paraguay (J. D. Haseman coll. March 31. 1909). One complete specimen, 
6 left valves. Rio Paraguay, Sido Luis de Caceres, Matto Grosso, Brazil (J. D. 
Haseman coll. May 25, 1909). One male, with soft parts, and seven specimens, 
shells only. 

Distribution.—Middle Parana above the junction with the Paraguay River in 
Argentina and Paraguay, and Paraguay River through Paraguay as far as Matto 
Grosso, Brazil. 

I disagree with previous authors, and regard this species as being distinct from 
D. hyleus. My specimens answer very well to the description and figures of 
D’Orbigny, and they differ from hyleus in their somewhat smaller size, in the more 
distinetly truncated (more steeply descending) posterior margin, forming a more 
distinet lower posterior angle, but chiefly in the beak-sculpture, which consists 
of a smaller number of bars, which are heavier, chiefly posteriorly, and are not so 
rugose. My specimens are also more swollen than the single individual of hylaus 
at hand, but the latter is, as has been stated, probably exceptional in this. 

The beak-sculpture is somewhat variable, chiefly in the length of the bars, 
which are from 15 to 20 mm. long, and generally cover more than half of the disk, 
but in the larger shells, sometimes less. There are twelve to fourteen radial bars, 


ORTMANN: SOUTH AMERICAN NAIADES. 477 


of which the seventh and eighth, or ninth and tenth, unite in the middle of the 
valve in a sharp angle; sometimes a short odd bar is found between these pairs. 
The bars are rather fine and sharp in front, but those behind, near the umbonal 
ridge become broad and rounded, their lower ends being irregular and indistinctly 
tubercular (much less so than in D. hyleus) occasioned by concentric lines cutting 
across them. These posterior bars also are distinctly longer than the anterior 
ones. Sometimes there are a few additional fine bars near the beaks on the posterior 
slope and below them a few oblique wrinkles. 

The posterior end of the shell is also somewhat variable, but it never is rounded 
and slightly biangular, as it is in D. hyleus. The posterior margin is obliquely 
descending, and the lower posterior end is bluntly pointed, the angle being more 
or less prominent. The lower margin of the shell is evenly convex in some speci- 
mens, in others it is more strongly convex a little back of the middle, forming a 
blunt angle. 

The specimen from Corumba is young, and the beak-sculpture covers all of 
the shell. It is also a little more compressed than the others, but agrees with them 
in all other characters. 


MEASUREMENTS. 
Length. | Height. Diameter. Beaks. 

Asuncion, No. 1......... 21 mm. 14 mm. =67 pr. ct. of L. 10 mm. =48 pr. ct. of L.. at 4. mm.=19 pr. ct. of L. 

Do. Dit aretetayy «ts 27 18) - =67 a 14 SS =52 He 6.5“ =24 = 

Do. hires ho ate ove 28 a 19 “ =68 ad 13 40) s 7 * =25 

Do. Be tees 33.5 “ | 22 “ =66 4 13 “ =39 4 8 =24 ‘ 
S. buisids Ca(G))\.... o-2- 108 “| 24 “ =62 a 15.5 =40 8 =21 5 
DiOrbienyis. fees woe. eloe h 18) 9 Se Sa) = 12 “) -=38 SF 8 =25 s 


| 
! 


Thus my specimens are on the average slightly higher and shorter, and some- 
what more swollen than the original, unless there are inaccuracies in the figure, 
which is not impossible, since the figure is 32 mm. long, while the text gives the 
length as 21 mm. 

Anatomy.—The only specimen (8S. Luis de Caceres) of which soft parts are 
at hand, is a male, and has the structure typical of the genus. The anal open- 
ing is slit-like, and about three-fourths of the length of the branchial. The 
branchial opening has fine papille. The palpi are triangular and rather small, 
the posterior margins are not connected. Inner lamina of inner gills connected 
with abdominal sac. Gill-structure typical. 


478 MEMOIRS OF THE CARNEGIE MUSEUM. 


3. DIPLODON HASEMANI Ortmann, sp. nov. 


Pl. XXXIV, figs. 1 to 4, shells; Pl. XLVII, fig. 5, section of gills; text-fig. 4a (p. 
469), glochidium. 

Locality.—Rio Guaporé, near Rio Sao Simao, Matto Grosso, Brazil (John D. 
Haseman coll., July 20, 1909). Nineteen specimens investigated, all with soft 
parts; sex of the three smallest not ascertained; the rest were males and gravid 
females. 

Type-set: Carn. Mus. No. 61.5857, twelve specimens, among them four males 
and five gravid females, one with eggs, the others with glochidia. 

Description of Shell.—Shell small (max. length 28 mm.), solid, swollen, short, 
subovate, somewhat pointed behind. Diameter 67 to 72 pr. et. of length, as against 
59 to 68 pr. ct. in D. guaranianus. Valves not gaping. Dorsal margin gently 
convex, passing gradually or with a blunt angle into the anterior margin, which 
is sometimes almost truncated. The posterior upper margin forms an obtuse, 
rounded angle with the posterior margin, the latter descending obliquely, gently 
convex, forming with the lower margin a rather distinet, but blunt posterior ter- 
mination of the shell, which is little elevated above the base-line. Lower margin 
gently and uniformly convex, passing in a regular curve into the anterior margin. 
The anterior portion of the shell does not appear appreciably narrower than the 
posterior, or very little so. 

Valves convex, more so in older specimens, with a rather distinet, but rounded 
umbonal ridge. Posterior slope subtruncated, a little compressed and elevated 
in the middle. Greatest diameter of shell 42 to 55 pr. ct. of length (82 to 52 pr. ct. 
in D. guaranianus). This greatest diameter located more forward toward the 
beaks than in D. guaranianus. Beaks somewhat swollen, but little elevated above 
the hinge-line, located at 25 to 28 pr. ct. of the length. Beak-sculpture of the 
hyleus-type, strongly developed, the posterior bars thicker and longer than the 
anterior. They cover 10 to 15 mm. of the shell, that is to say, hardly half of it 
in larger specimens. There are from fourteen to sixteen of them, and the ninth 
and tenth generally meet at an acute angle, with sometimes a short odd one between 
this pair. The anterior bars are sharp, the posterior ones broader and rounded, 
but not so much as in D. guaranianus. There are often three or four additional 
finer bars upon the posterior slope, and some oblique wrinkles behind and below 
them. The lower ends of the bars are but faintly cut up into tubercles. A lanceo- 
late, rather short, lunula may be present in the larger specimens. 

Epidermis with numerous, concentric, irregular striz, finely lamellar in young 


ORTMANN: SOUTH AMERICAN NAIADES. 479 


specimens, and in older specimens on the posterior slope and toward the lower 
margin. Fine, obscure, radial lines all over the shell. Color rather uniformly 
dark brown, but in young specimens there is a distinct indication of a yellowish 
concentric band, or the region near the beaks may be of this color (suggesting the 
color-pattern of D. trifidus). 

Hinge-line gently curved. Ligamental sinus over the middle of the lateral 
tooth, or a little farther back. Lateral teeth curved, one in right, two in left 
valve. In one specimen in the right valve there is a distinct, but low, accessory 
lateral below the normal one. Asa rule two pseudoecardinals in each valve. They 
are not much compressed and not much elongated, but rather stumpy, and are 
very much eut up, especially the posterior ones in each valve. The anterior 
pseudocardinal in the right valve is more distinctly compressed, but may be very 
small or even obsolete, and there may be a trace of a third pseudocardinal behind. 
The posterior pseudocardinal in the left valve is very variable in shape and size. 

Cavity of shell and of beaks moderate. Nacre in all specimens whitish. 
Anterior adductor-scar deep, even in young specimens, irregularly rounded. An- 
terior retractor-scar separated from it, small and deep. Anterior protractor- 
sear united with the adductor-scar. Posterior adductor-sear less distinet, sub- 
triangular, with a short upper process formed by the posterior retractor-scar. 
Pallial line distinct. Dorsal sears few, located in beak-ecavity and close to hinge- 


plate. 
MEASUREMENTS. 

No. \Sex.| Length. | Height. Diameter. | Beaks. Figures. 

EDs lieteapeleeo) mm.| 9 mm. =72 pr. ct. of L.) 5.5 mm. =44 pr. ct. of L.| at 3.5 mm. =28 pr. et. of L. 

> aera be fan fet s 10 87, 7 “S47 Us + Ss =D. m 

2a..| o | 18 Soe ides ati s 7.5 ‘ =42 Ey 5 “ =28 oe } 

4.2 .| 2) 23 nS 16 i) 5S ll ee ees i Gia. = 28 “ | Pl. XEXEXIV, fie. 3. 
GES a ebay Se Maly Oe a 12 aff nf 7 aii, a 

TeAolpeOus es 18 ‘ =69 es We OO Sie 2 : 

9...) 9 | 28 | DEO C0) H 14 Eo = G0) 7 2.) " PPO RCV, figs, 2. 
10...!o" | 27.5“ [20 ie Ge 15 =ab 7 = 26 = Pl. XXXIV, fig..1. 


I cannot discover any sexual differences in the shell. 

Remarks.—There is no question that this species is very closely allied to 
D. guaranianus, and it may be described as a small, short, rather swollen D. guarani- 
anus, with the posterior end of the shell a little sharper, the posterior ridge a little 
more distinct, and beak-sculpture less developed. Since I possess a good number 
of specimens of D. hasemani, and also a fair number of D. guaranianus, 1 do not 
doubt the specific distinctness, since the geographical distribution also differs. 
D. guaranianus belongs to the Parand and Paraguay Rivers, while D. hasemani is 
from the Guaporé, tributary to the Amazons-system. However, a former con- 
nection of these systems is indicated by the close affinity of the two species. 


480 MEMOIRS OF THE CARNEGIE MUSEUM. 


Anatomy.—I have before me many males and gravid females with soft parts. 
It should be noted that the smallest gravid females are only 16 mm. long and that 
this fact indicates that this is a small species, not growing to a larger size, as my 
material shows, reaching the maximum length of 28 mm. 

Anal opening short, slightly shorter than the branchial opening, the latter . 
very short, with few but distinct papillae. Palpi subtriangular, lower margins 
convex, posterior margins searcely connected. Gillsnormal. Inner lamina of inner 
gill entirely connected with abdominal sac. In the larger gravid females the 
middle of the inner gill is marsupial, leaving a little less than one-fourth of the 
gill both at the anterior and posterior ends non-marsupial. In the smaller females 
the marsupial part is smaller. The swelling of the charged marsupium is moderate 
and the gills are charged to near the edge. In the marsupial part the interlaminar 
connections are arranged in interrupted vertical septa. Since no sterile females 
are at hand, the exact arrangement could not be seen in a face view, but from sec- 
tions (Plate XLVII, fig. 5) it is evident that it is very likely more or less reticulate. 

Glochidia (Text-fig. 4a, p. 469) subtriangular and margined, without hooks. 
Measurements, without margin: L. 0.30 to 0.31 mm.; H. 0.24 to 0.25 mm.; with 
margin: L. 0.35 to 0.86 mm., H. 0.29 to 0.30 mm. The presence of eggs and 
glochidia on July 20 should be recorded with respect to the breeding season. 

Color of Soft Parts in Alcohol.—Foot blackish in its distal part, this color 
separated in a sharp line from the light basal part. Rest of soft parts whitish. 


4. DiIpLopon TRIFIDUS (Lea) (1860). 
Diagram of Soft Parts (See Text-fig. 1, p. 455). 
Unio trifidus Lma, Obs. X, 1868, Pl. 44, fig. 295. 
Diplodon trifidus Simpson, 1900, p. 884; 1914, p. 1272. 

Type-locality—‘‘ Buenos Ayres.”’ Never reported again since its original 
description. 

New Localities —Centre of Rio Guaporé, near Rio Sao Simao, Matto Grosso, 
Brazil (J. D. Haseman coll., July 20. 1909). Six specimens, all with soft parts. 
In the three smallest the sex is uncertain (they have the male structure); the others 
are two males and one (the largest) a gravid female with eggs. Rio Guaporé, Sao 
Antonio de Guaporé, Matto Grosso, Brazil (J. D. Haseman coll., July 31, 1909). 
One male with soft parts. 

Distribution.—I have doubts as to the correctness of the loeality originally 
given. Von Ihering (1893, p. 118) lists this species with those from the La Plata 
drainage, but he rests entirely upon Lea. The latter received his single specimen 


ORTMANN: SOUTH AMERICAN NAIADES. 481 


from D’Orbigny with the above locality; but it is quite possible that a mistake 
was made, since D’Orbigny also collected in the Amazon system in Bolivia, in 
the general region, whence our specimens come. Nobody else ever re-discovered 
this species in the La Plata, although frequent collections have been made. Our 
material is beyond any doubt this species, and the locality is authentic. 

The set, although containing only six specimens, comprises young and old, 
males and females, and thus it is worth while to give a full description. 

Description of the Shell—Of medium size, growing larger than any of the 
preceding species (maximum length 58 mm.; the type is 42 mm., according to 
Simpson), rather solid. Outline subelongated, subelliptical, or long-ovate, rounded 
in front, pointed behind. Height 41 to 54 pr. ct. of length. Valves not gaping. 
Dorsal margin straight in young specimens, very gently curved in older ones. 
Anteriorly the dorsal margin forms an indistinct angle with the anterior margin 
in young individuals; in old ones it passes into it gradually. Posteriorly the dorsal 
margin forms a very obtuse angle with the posterior margin, or, in the largest 
specimen, passes gradually into it in a gentle curve. Posterior margin obliquely 
descending, gently curved, meeting the posterior portion of the lower margin in a 
blunt, but distinet, point, which is elevated above the base-line, but nearer to the 
latter than to the line of the upper margin. Ventral margin gently and rather 
regularly convex, its lowest point slightly behind the middle of the shell, ascending 
in front and behind it. In front it curves up into the anterior margin. Thus the 
shell has a long-ovate, almost subelliptical outline, with the anterior end only 
slightly narrowed and rounded, and the posterior more tapering and bluntly pointed. 

Valves moderately convex, convexity rather uniform all over the disk, but 
strongest near the beaks and upon the umbonal ridge, which forms a rounded, but 
rather distinct, angulation running toward the posterior point. Posterior slope 
somewhat compressed. Diameter 23 to 36 pr. ct. of length. Beaks not swollen, 
hardly elevated above the hinge-line, located at 18 to 25 pr. ct. of the length. Since 
the shell is more swollen towards the beaks, the latter appear depressed, chiefly 
in old specimens. Beak-sculpture distinct and well developed, consisting of about 
sixteen radial bars; the anterior bars are shorter (about 5 mm. long), the posterior 
much longer, chiefly upon the umbonal ridge, where they are 15 mm. long, or even 
more. There are two systems of these bars; eight or nine anterior, and seven or 
eight posterior bars. In the middle of the shell one or two pairs unite at a sharp 
angle, and sometimes a short, odd bar stands between the innermost pair. The 
anterior bars are sharp; the posterior ones are also rather sharp near the beaks, 
but towards their lower ends they gradually become thicker and rounded, broaden- 


482 MEMOIRS OF THE CARNEGIE MUSEUM. 


ing and flattening, and finally disappearing. These broad bars are conspicuous 
chiefly immediately in front of the umbonal ridge, and are distinetly seen even in 
our largest specimens, where the beaks are greatly eroded. All these bars are 
smooth, except for the concentric strive of the epidermis which cut across them. 
In some of my young specimens there are a few oblique wrinkles upon the posterior 
slope, but there are hardly any radial bars, except one, fine, and short, close behind 
the broad bars of the umbonal ridge. There is a narrow and short lunula in front 
of the beaks. 

Epidermis smooth, but with numerous, irregular, concentric lines, which be- 
come sublamellar upon the posterior slope and near the lower margin. There are 
also numerous fine, irregular, but straight, radiating lines on the disk below the 
beak-seulpture. The posterior slope has no radial ridges or furrows. Color of 
epidermis dark to light green, with concentric bands of yellow-brown. The three 
young specimens are light golden-brown towards the beaks, and light green towards 
the margins; in the old specimens the green color prevails, and becomes quite dark, 
but is interrupted by one or two lighter bands of brownish. No traces of color- 
rays present. 

Hinge-line almost straight or very gently curved. Ligamental sinus over the 
posterior third of the lateral teeth. One lateral in the right, two in the left valve, 
rather long, distinct, and in old shells gently curving downward behind. Pseudo- 
cardinals very variable. Lea describes them as trifid in both valves, but this is 
not always the case. Of our largest specimen it may be said that the right valve 
has three teeth: the middle one the largest, directed obliquely downward and for- 
ward, triangular, narrow above, broader below, and deeply longitudinally cleft 
into three ridges; in front of it is an anterior, narrow, compressed tooth, which 
is connected with the middle one above; behind the largest pseudocardinal is a 
deep groove, followed by small, ragged elevation of the hinge-plate representing 
the third tooth. The left valve has one large posterior tooth, which is ragged and 
fits into the groove behind the middle tooth of the other valve (including the small 
elevation behind it), and in front of it is a narrow lamellar tooth, fitting into the 
space between the first and second teeth of the right valve. In the groove be- 
tween these two teeth of the left valve are two low ridges, corresponding to the 
clefts of the large tooth of the right valve. In our second largest specimen (No. 1) 
the same general arrangement is seen, but the anterior tooth of the right valve is 
very low, while the third (posterior) is more distinct and triangularly elevated. 
The left valve has two teeth. All these teeth are much less ragged, and the clefts 
of the middle tooth of the right valve are lacking, and also the corresponding ac- 


ORTMANN: SOUTH AMERICAN NAIADES. 183 


cessory ridges of the left valve. Similar, but rather variable, conditions are seen 
in the younger individuals and the specimen from $8. Antonio. The rule is that 
there are three teeth in the right, but only two in the left valve. 

Cavity of the shell moderate, that of the beaks shallow. Nacre shining, snow- 
white in my specimens, in two (No. 1 and the one from 8. Antonio) with a faint 
salmon blush in the cavity of the shell. Anterior adductor-scar deeply impressed 
even in young specimens, irregularly rounded or broadly subelliptical. Anterior 
retractor-sear located above it, separated from it, deep, small. Anterior protractor- 
sear connected with it. Posterior adductor-scar distinet, but much less impressed, 
subovate or subtriangular, with a rounded or triangular appendix above, formed 
by the posterior retractor-scar. Pallial impression distinct. Dorsal scars five or 
Six, In cavity of beaks, placed irregularly, or in an oblique line. 

There are no sexual differences in the shell. 


MEASUREMENTS (SPECIMENS FROM SAO SIMAO). 


No. Sex. Length. | Height. Diameter. Beaks. 
Choa anb6e ? 21.5 mm. | 9 mm. =41 pr. et. of L. 5 mm. =23 pr. et. of L. at 4.5 mm. =21 pr. et. of L. 
Bia oP rol 34 or 16 “ =47 Ni 10 “ =29 = 7 “ =21 ig 
ey me ter rot 56 A 30 “ =54 i 17 =3}1) 14 =25 
CAS Ping SRa, 2 58 : 29 “ =50 a: 21 =36 14 =24 
Lea’s figure... ... ZOE Ea If ey ‘! (i =36 7.5 =18 


In Lea’s text there is apparently an error with respect to the height, since the 
measurement would yield the absurd figure of 89 pr. et. of the length. According 
to the figure Lea had a specimen with the beaks a little more anterior than any of 
mine, but otherwise rather closely agreeing with them. 

Remarks.—This species is related to those of the hyleus-group, chiefly to 
D. guaranianus, but it is easily distinguished by its long-ovate shape, with pointed 
posterior end, and by the beak-sculpture, which, although of the same type, does 
not extend so far upon the disk. A good character is furnished also by the color 
of the epidermis and its concentric bands, though we have seen that this pattern 
is at least indicated in young D. hasemani. Lea compares D. trifidus with D. 
burroughianus and parallelopipedon, but there hardly is any close relationship to 
the former, and but a superficial resemblance to the latter. I think it belongs to 
the hyleus-group, and may be characterized as an extremely elongated member 
of that group, in which the beak-sculpture is not quite so fully developed as in 
the other species. 

Anatomy (Text-fig. 1, p. 455).—The three smallest of my specimens could not 
be satisfactorily examined to ascertain the sex, but the gills did not show the mar- 


484 MEMOIRS OF THE CARNEGIE MUSEUM. 


supial structure, so that they may be males. Of the others, three are males, and 
one is a gravid female with eggs. The fact that this was collected on July 20 gives 
an indication of the breeding season. 

Anal opening (a in text-figure) closed above, without forming a supra-anal. 
Closed part (s) two to three times as long as the anal; the latter (a) slit-like, short, 
shorter than the branchial opening. Inner edge of anal practically smooth. 
Anal separated from the branchial by a solid bridge (¢) formed by the union of 
the mantle-margins. Branchial opening (b) a little over twice as long as the anal, 
with distinct papillee on inner edge; mantle-edges not united in front of it. Palpi 
(h) subtriangular, the lower margins slightly convex, the posterior margins con- 
nected at the base. 

Gills (¢ and 0) rather long and moderately wide. The inner (7) wider than 
the outer (0) chiefly in front. Outer gill narrowing behind and before, its anterior 
end near the highest point of the mantle-attachment-line. The inner gill has an 
almost straight lower margin, and is only little narrower anteriorly; its anterior 
end is immediately behind the palpi. Inner lamina of inner gill entirely connected 
with abdominal sac. 

Structure of gills normal. In the male both gills have fine, scattered, and 
interrupted interlaminar connections, running parallel with the gill-filaments, 
but without forming complete septa or water-tubes. In the gravid female, the 
eggs are contained in the large middle section of the inner gill (7), leaving free 
less than one-fourth of the gill at the anterior and at the posterior extremity, and 
also leaving free a narrow zone along the margin. This marsupial part has the 
interlaminar connections strongly developed, in the shape of interrupted septa, 
forming incomplete, intercommunicating water-tubes, filled by the eggs in a dense 
mass, not separated into placentze. Since no sterile females are at hand, the exact 
arrangement of the interlaminar connections in a face view could not be made out. 
The charged marsupium is somewhat swollen and distended, so that the inter- 
laminar connections have stretched out. The outer gill of the female has the 
structure of the gills of the male. 


2. Group or Diplodon granosus. 


Shell subovate or subtrapezoidal, rather elongated, not distinctly pointed 
behind, straight, not distinctly higher in the posterior part, nor oblique. Beak- 
sculpture well developed, but fine, and characteristically cut up into numerous 
fine nodules or granulations, thus obscuring the radial arrangement. The granular 
sculpture often continued a good distance upon the disk. 


ORTMANN: SOUTH AMERICAN NATIADES. 485 


The essential character of this group is in the beak-sculpture, which, however, 
is very variable, although the granular structure is always more or less evident. 
It is hardly possible to give any additional characters, except that the hinge- 
teeth are moderately developed, subeompressed, and hardly ever stumpy. Two 
pseudocardinals are in each valve, but sometimes there are reductions. 

I have very little material representing this group. The soft parts of only 
two specimens are at hand, one too young to be of any value, the other a male. 
Thus nothing can be said about the structure of the female. All my specimens 
seem to belong to one species, which is very variable, and has a very limited range 
in the coastal streams of eastern Brazil. 

The genetic connections of this group likewise cannot be properly ascertained. 
The beak-sculpture does not seem to be very primitive, when compared with the 
other species of the genus. In the shape of the shell and the hinge, there is simi- 
larity to the next group (chilensis), which possibly may be the most primitive of 
the genus. 


5. DreLoDON GRANOSsUS (Bruguiére) (1792). 


Compare: Unio multistriatus Lea, Von InerinG, 1890, p. 165. 
Unio psammactinus BRONN, Von IHERING, 1893, p. 107. 
Diplodon expansus VON THERING, 1910, p. 134. 

Diplodon granosus (BRUGIDRE), Stupson, 1914, p. 1250. 

I am inclined to accept the earlier opinion of Von Ihering (1890), and that of 
Simpson, that a number of so-called “species,” of which Simpson has given a full 
synonymy, belong here. Possibly several others should be included. 

Type-locality.— Brazil and Guiana. 

== 

Additional Localities.—Rio de Janeiro (psammactinus, Philippi) (Von Ihering) ; 
coastal streams in eastern Brazil, between Rio de Janeiro and Bahia, but not to 
the south of Rio (Von Ihering); Rio Negro, Prov. Rio de Janeiro, Distr. St. Rita 
(Dunker’s coriaceus, Von Ihering); Tayuara, Distr. Canta Gallo, Prov. Rio de 
Janeiro (Von Ihering); Rio Parahyba do Sul, Rio de Janeiro (Von Ihering); Nova 
Friburgo, Rio de Janeiro (Von Thering). Rio Paraguassi, Bahia (Von Ihering, 
1910, p. 139, as multistriatus Lea). Rio Doce, Espirito Santo (Von Ihering, 1910, 
p. 134, as expansus Kuester). 

New Localities—Mountain creek, Raiz da Serra, near Santos, Sio Paulo, 
Brazil (J. D. Haseman coll., July 26. 1908). One specimen with soft parts, male. 
Rio Ribeira, Iporanga, Sio Paulo, Brazil (J. D. Haseman coll., December 1. 1908). 
Two specimens, young, one with soft parts of the male type. 


486 MEMOIRS OF THE CARNEGIE MUSEUM. 


In addition, the Carnegie Museum possesses two specimens labeled “ellipticus, 
Brazil,” from the Holland Collection, and one specimen labeled ‘“multistriatus, 
Brazil,” from the Juny Collection. 

Distribution —The new localities represented in the collection made by Hase- 
man extend the range southward (southwestward) along the coast of Brazil beyond 
Rio de Janeiro into the southern portion of the state of Sao Paulo in the small 
coastal streams. The established range thus reaches from the Rio Paraguassu 
in the North to the Rio Ribeira in the South. 

Remarks.—My material is entirely insufficient for the study of the various 
forms regarded as belonging here. Originally Von Ihering was inclined to unite all 
these forms with granular beak-seulpture into one species; but later he divided them 
according to the character of the beak-sculpture, although he admits that there is 
great variation in this respect. Simpson unites them again, at least in part, but 
he lets granuliferus Dunker stand, and even adds a new species, D. semigranosus." 

My specimens also vary in the development of the beak-sculpture and in the 
shape of the shell, but they might very well be forms of one and the same species. 
The two soft parts at hand are those of males, and the structure of the female is 
unknown. 

The two young specimens from Iporanga show the granular beak-sculpture 
very well, and I should eall them D. granosus by all means. Simpson (1914, p. 
1249) has described from the same river-system (Rio Ribeira) at Iguapé, Sao Paulo, 
Brazil (near the mouth), a D. mimus, and Marshall (1917, p. 383, pl. 51, figs. 3-6) 
has redeseribed and figured it. It is founded upon two specimens, larger than 
mine, and differing somewhat from each other in their proportions, and also from 
my specimens, but the differences may be individual. The measurements are: 


Length. Height. | Diameter. 


SHON Gooinagashosoherl| qh Won, 28 mm. = 76pr.ct.of L. | 17 mm. = 46pr. ct. of L. 

WAT HS) OVI Miles Greteuctekss Gan-crn gi A b-Beea)y co | @27 160 ie | 15 «= 3: 

My specimen............| 29 “ | 17.5 “ =60 «“ I Sgs5 oe eeeog a 
ener mene Soe & ee se 


My specimens agree very well with the figures and description, except that there 
is no lurid-purple in the nacre, which is dull (lurid) whitish. 


13 Habitats: “Sao Paulo River” (location unknown); “ Ponte Grande’ (location unknown); 
“ Qs Perus,” Sao Paulo, Brazil. Marshall (1917, p. 387) redeseribes and figures this species, and gives 
as type-locality: Rio Tieté, Sao Paulo, and the additional localities ‘‘ Ponte Grande, Sao Paulo; Os 
Perus: and Ponta Grossa, Parand.’’ The location of Ponte Grande is still unknown. Ponta Grossa 


is on the headwaters of the Rio Tibagy, tributary to the Parand Panema. 


ORTMANN: SOUTH AMERICAN NAIADES. 487 


The beak-sculpture of Simpson’s species is unknown, being entirely eroded. 
It may be that my specimens are this, but I hesitate to unite D. mimus with granosus, 
before the beak-sculpture of the former has been described. 


3. Group oF Diplodon chilensis. 


Shell rather compressed, flattened upon the sides, subelliptical, subovate, 
subtrapezoidal, more or less elongate, not distinctly pointed behind, straight, 
and not distinctly higher in the posterior part, nor oblique. Beak-sculpture 
simple, with narrow, straight, uninterrupted radial bars, restricted to the region 
of the beaks, and not extending far upon the disk. Two of the median bars may 
be joined at their lower ends. 

The generally subtrapezoidal shape of the shell, with flat sides, and the simple 
character of the beak-sculpture are the chief characters of the group, which may 
represent the most primitive type within the genus. The posterior end of the 
shell is mostly not pointed, but more or less rounded, and the posterior ridge is 
rather indistinct, not prominently angular. 

A great number of ‘species’? belong here, which are extremely hard to dis- 
tinguish. It is in this group that I encountered the greatest difficulties in the 
identification of the species, and even at present I am not satisfied with the results. 
This is the more to be regretted, since I have abundant material with soft parts of 
some of these forms and have found that there are differences in the anatomy, 
which to all appearance are of specific value. 

After many attempts to group these forms, I have finally concluded that the 
best way, the one that is least liable to lead into error, is to treat these forms geo- 
graphically. It is not very likely that the same identical species occurs in widely 
separated river-systems. 

Forms of this type are found over nearly the whole continent, but apparently 
they are rare or missing in the region of the great depression which runs from the 
La Plata up the Paraguay to the Amazon-drainage. I shall begin with the forms 
from Chile and Patagonia, and proceed then in the direction toward Brazil, going 
from South to North. 


1. SPECIES FROM CHILE AND PATAGONIA. 


I have very insufficient material of this group, and cannot express any positive 
opinion about the species. But it seems that all, or nearly all, of the forms known 
from Chile belong here. Simpson (1914, p. 1257) admits ten of them: chilensis 
Gray, solidulus Philippi, gassiesi Kuester, aplatus Reeve, moline Philippi, modestus 


488 MEMOIRS OF THE CARNEGIE MUSEUM. 


Kuester, atratus Sowerby, obtusus D’Orbigny, chiloénsis Kuester, awreus Simpson. 
But the differential characters of these are very obscure, and I should not be as- 
tonished if some of these names should prove to be synonyms. 

Similar forms are known from the eastern foot of the Cordilleras in Patagonia, 
in the drainage of the Rio Negro. Of these the following material is at hand: 


6. DreLopon PpaTAGonicus (D’Orbigny) (1835). 


Unio patagonicus D’OrBIGNyY, 1848, p. 610, Pl. 70, figs. 1-4. 
Diplodon patagonicus Simpson, 1900, p. 885; 1914, p. 1275; Prussry, 1911, p. 610. 

Type-locality.—Rio Negro, 10-12 miles above its mouth. 

New Locality.—Rio Limay, Patagonia (Received in exchange from W. Israél), 
one right valve. 

Distribution.—Rio Negro and its tributary Rio Limay in Patagonia. 

The specimen at hand is very poor, with the epidermis worn off, but it is un- 
doubtedly this species, which is characterized by its elongated outline and a shallow 
radial groove upon the posterior slope. 

This species is not at all related to D. parallelopipedon (Lea), with which 
it has been associated by Simpson. It has, indeed, a similar elongated outline, 
but the characteristic strong and elevated posterior ridge of the latter species is 
entirely absent. 


7. DIPLODON FRENZELI (Von Ihering) (1893). 


Unio frenzelii Von InERING, 1898, p. 111, Pl. 4, fig. 12. 
Diplodon huapensis Bartscu, 1906, p. 394, Pl. 27, fig. 1; Pl. 28, fig. 1; Pl. 29, fig. 2. 
Diplodon frenzeli and huapensis, Simpson, 1914, pp. 1264, 1265. 

Type-locality.— Patagonia. 

Other Localities.—Patagonia, foot of the Cordilleras (Von Ihering); small 
lake on Victoria Island in Lake Nahuel Huapi, Argentina (Bartsch, hwapensis). 

Locality Represented in Carnegie Museum.—Lake Nahuel Huapi, Argentina 
(C. H. Eigenmann coll., 1919). One gravid female with soft parts. 

Distribution.— known from Patagonia, at the foot of the Cordilleras in the 
region of Lake Nahuel Huapi (Rio Negro drainage). The locality “Chile” given 
by Von Ihering is rather vague; and ‘Os Perus, Sao Paulo, Brazil,” given by 
Simpson for frenzeli is probably incorrect. 

My material is too poor to give a full account of this species, but I am sure 
that my only specimen belongs here, and I also believe that huapensis is the same. 


4 Unio patagonicus Reeve, XVI, 1865, Pl. 21, fig. 93, is not this. 


ORTMANN: SOUTH AMERICAN NAIADES. 489 


This species has the indifferent and uncharacteristic outline of the forms of 
the chilensis-group: subelliptical or subtrapezoidal, with upper and lower margins 
subparallel, and rather elongated and compressed shell. _ It is, however, remarkable 
for the anterior location of the beaks (18 or 19 pr. ct. of the length). There is no 
radial furrow or groove on the posterior slope. 

The color of the epidermis of my specimen (the largest known) is dark brown, 
and the epidermis is wrinkled with concentric lamellae, but it has been largely 
eroded. According to Von Thering, the color is dark brown in the larger specimens, 
but dark olive in smaller ones, sometimes with lighter green in places. The color 
of huapensis is brown posteriorly, grading to wax-yellow anteriorly. 

In all other respects, chiefly in the hinge-teeth, my specimen agrees with the 
description of frenzeli; only the posterior end of the shell is a little more broadly 
rounded, but not very different from the specimen figured by Von Ihering on plate 
4, fig. 127. 

D. huapensis has been compared by Bartsch with frenzeli, and he says that it 
can readily be distinguished from it by the narrower outline, that means to say by 
the height being less in proportion. This, however, is not correct, as can be seen 
by comparing the measurements. 

The only difference I can see in huapensis is the more tapering posterior end. 
But since this species is founded upon two specimens, of which only one has been 
figured, this might very well be an individual character. 

In the following measurements I leave out Von Ihering’s specimens from Chile, 
which appear to me a little doubtful. 


MEASUREMENTS. 
Length. Height. Diameter. Beaks. 
Huapensis (figure).......... 53 mm. | 25.5 mm. =48 pr. ct. of L.. 14 mm. =26 pr. ct. of L. at 10 mm. =19 pr. ct. of L. 
Do. (type, text)...... }55 “ 25.9)! =A, ¥ 14.5 =26 os 
Do. ext) iiss oscs § Ui os Zico | = AS Sf 16 ‘ =28 
Frenzeli 5b Von Ihering. ....| 56“ | 26 ee Se Gh 16  =29 “ LO Ls 
Do. 5a Von Ihering.....)58 ‘ | 28 “ =48 es 17 “ =29 s 11 “ =19 
Do. Von Ihering........ 68 “ | 34 el si 20 0 . ie 
My specimen (9).......... Les | ater Siu! a 16 i 5} e 13 “ =18 


Thus my specimen is more compressed than any of the others ; however, a 
variation of the diameter from 23 to 29 pr. ct. is not at all unusual. 

Anatomy.—The specimen at hand has been preserved with the soft parts, and 
proved to be a gravid female with glochidia. 

Color of soft parts whitish, with black pigment near anal and branchial open- 
ings extending forward a good distance along the margin of the mantle, and be- 
coming brown. 


490 MEMOIRS OF THE CARNEGIE MUSEUM. 


Bartsch has given a description of the soft parts of hwapensis, which refers 
chiefly to the general features, the color, the structure of the siphons, and the 
shape of the gills and palpi. But no particulars as to the structure of the gills are 
given. 

Anal opening slit-like, closed above, closed part about four times as long as 
the open, the latter with the inner edge smooth, and separated from the branchial 
by a solid mantle-connection. Branchial opening with distinet papille. Palpi 
of moderate size, subtriangular, lower margins curved, posterior margins not 
connected at base. 

Gills nearly of the same width posteriorly, the inner much wider than the 
outer anteriorly. Outer gill subtriangular, its anterior end at the highest point 
of the mantle-attachment-line. Inner gill with gently convex margin, very little 
narrower anteriorly, broadly attached in front, its anterior end immediately be- 
hind the palpi. Inner lamina of inner gill entirely connected with abdominal sac. 
Interlaminar connections of non-marsupial gills weakly developed, scattered. 
Marsupium located in the inner gill, but not occupying all of it, leaving nearly 
one-fifth of the gill free anteriorly, and about two-fifths posteriorly, so that the 
marsupium is distinetly shifted forward, lying in the second and third fifth of the 
gill (from the anterior end). Interlaminar connections of the marsupium forming 
interrupted septa, the septiform structure apparently prevailing (this is not quite 
clear, since the structure is obscured by the masses of glochidia). The charged 
marsupium is a little swollen, and the glochidia fill it in a loose mass, not being 
conglutinated. 

Glochidium subtriangular, strongly oblique, with the point of the lower margin 
located vertically below the posterior end of the hinge-line. Hooks are present 
and of the normal S-shape. LL. 0.25, H. 0.20; L. of hooks: 0.05 mm. Compared 
with other species, the glochidium is rather small. 


2. SPECIES FROM COASTAL STREAMS OF SOUTHERN BRAZIL. 


It is a noteworthy fact that species of the chilensis-type seem to be absent 
from the system of the Rio de la Plata (with the exception of the drainage of the 
upper Parand). They also seem to be absent in the great Amazons-basin, and 
northward. But they are found rather plentifully on the Brazilian plateau, be- 
ginning at its southern extremity, in the coastal streams in Rio Grande do Sul, 
going thence northward, and crossing over in Sao Paulo and Paranda into the drain- 
age of the upper Parana River. 

We shall take up first the species of the coastal streams, and I wish to call 


ORTMANN: SOUTH AMERICAN NAIADES. 491 


attention (as has been done by Simpson in the case of D. mimus) to the great re- 
semblance of these shells, not only among themselves, but also to the North 
American Elliptio complanatus (Dillwyn), distributed over the Atlantic streams 
of the eastern coast of the United States from Georgia to Maine. This resemblance, 
of course, is only external and superficial. Closer examination of the hinge, of 
the adductor-sears, and, if visible, of the beak-sculpture, at once reveals important 
differences. The anatomy is entirely different. 


8. DreLopon IMITATOR Ortmann, sp. nov. 
Shells: Pl. XXXIV, figs. 5, 6,7; Pl. XXXV, figs. 1,2. Anatomy of gills: Pl. XLV, 
fig. 1. Section of gills: Pl. XLVII, fig. 6. Glochidiwm: text-fig. 4b (p. 469). 

Type-locality—Rio Vaceahy-mirim, Santa Maria, Rio Grande do Sul, Brazil 
(J. D. Haseman coll., January 29. 1909). Twenty-three specimens, all with 
soft parts, among them males, barren and gravid females, with eggs and with 
glochidia. Type-set: Carn. Mus. Cat. No. 61.9248. (This is in the drainage of 
the Rio Guahyba-Jacuhy, far up in the headwaters). 

Additional Locality.—Rio Jacuhy, Cachoeira, Rio Grande do Sul, Brazil (J. D. 
Haseman coll., January 26. 1909). One barren and one gravid female, with eggs, 
both young. (This is farther down, in the middle part of the Rio Jacuhy.) 

(Originally there were thirty-four specimens from the type-locality at my 
disposal, all with soft parts.) 

Only once before has a form of this group been reported from the Guahyba- 
drainage, viz. D. martensi Von Ihering, from Taquary and Santa Cruz (probably 
from tributaries of the lower Jacuhy (See Von Ihering, 1893, p. 102). But these are 
not typical martensi, the original of the latter being “ probably from Sao Paulo).””” 
The dimensions of these specimens from Rio Grande do Sul given by Von Ihering 
agree fairly well with those of the real U. martensi, chiefly the relation of height 
to length: 49 pr. ct. in two specimens from Rio Grande do Sul, 49 pr. et. (text) or 
53 pr. ct. (figure) in martensit. But these dimensions do not agree with my speci- 
mens, where the height ranges from 55 to 64 pr. ct. and never falls as low as in 
martenst. The diameter of martensi is also greater than in my material. For 
this reason I am compelled to describe my shells as a new species. 

Description of Shell—Of medium size (maximum length 80 mm.), moderately 
solid, rather thin when young, compressed (diameter 26 to 33 pr. et. of length), 
subelliptical, subovate, or subtrapezoidal, moderately elongated (height 55 to 


Tt is much to be regretted that the type-locality is not better known. It is very doubtful, on 


account of the great similarity of these forms, whether the real martensi can ever be positively identified. 


492 MEMOIRS OF THE CARNEGIE MUSEUM. 


64 pr. ct. of length). Valves not gaping. Dorsal margin nearly straight or very 
gently convex, passing gradually into the anterior margin (rarely forming an in- 
distinct angle). Posterior upper margin forming a blunt angle with the posterior 
margin or passing gradually into it. Posterior margin obliquely descending, 
more or less curved, and curving more strongly into the lower margin, without 
forming a distinet posterior angle. The lower posterior end of the shell is rounded, 
but hardly biangular. Lower margin in young specimens gently convex, in older 
ones it is rather straight in the middle. Anterior end of shell not, or very little, 
narrower than the posterior end. The shell is thus rather straight and not oblique. 

Valves only slightly convex, rather flattened upon the sides, with the posterior 
ridge very indistinct and broadly rounded. Posterior slope somewhat compressed. 
Greatest diameter near the middle of the shell, but not posterior to it. Beaks 
not swollen, and not elevated, located at from 20 to 28 pr. ct. of the length. Beak- 
sculpture consisting of about fourteen to sixteen rather sharp and fine, short, radial 
bars, 5 to 7 mm. long, those upon the posterior ridge hardly longer than the rest, 
and none of them uniting in the middle of the shell with their lower ends. No 
distinct granulations present, but sometimes there are a few irregular oblique 
wrinkles upon the posterior slope near the beaks. A short, narrow lunula in older 
shells. 

Epidermis in young specimens rather smooth and shining, but with fine, ir- 
regular, concentric striae, nowhere lamellar. In old specimens it is less smooth, 
chiefly on the posterior slope and toward the lower margin with more crowded 
and rougher striz. Crinkled radial lines hardly indicated upon the shell. Color 
in young specimens greenish bronze or brownish, sometimes with indistinet brown- 
ish concentric bands, in older shells greenish tints disappear, and the epidermis 
is dull brown or blackish brown. ; 

Hinge-line gently curved. Ligamental sinus over the middle of the lateral 
tooth or slightly behind it, in older shells over its last third. Laterals curved, one 
in right, two in left valve, somewhat rough posteriorly. Pseudocardinals normally 
two in each valve. In young specimens those of the right valve are obliquely and 
forwardly descending, compressed, the anterior low and narrow, the posterior 
higher and a little thicker, crenulated. In older specimens the posterior is thicker 
and becomes generally more triangular and stumpy. Those of the left valve of 
_young specimens are also compressed, but subtriangular and not very long, crenu- 
lated, the anterior one larger than the posterior. In old shells these two teeth are 
more stumpy, triangular, and not compressed. In rare cases reductions take place, 
chiefly with regard to the anterior tooth of the right valve, or with regard to the 


ORTMANN: SOUTH AMERICAN NAIADES. 493 


posterior in the left valve, which may become very small, and sometimes an ac- 
cessory third posterior tooth may develop in the right valve. Thus the pseudo- 
cardinals are quite variable in number, shape, size, compression, and development 
of rugosities. 

Cavities of shell and beaks shallow. Nacre blueish white or white, often 
discolored and with lurid tints (grayish purple) toward the beak-cavities, iridescent 
posteriorly. 

Anterior adductor-sear distinct and impressed, subtriangular. Anterior 
retractor-scar separated from it, small, round, deeply impressed. Anterior pro- 
tractor-scar connected with adductor-scar, forming a posterior process of it. Pos- 
terior adductor-sear shallow, subtriangular, with an upper process formed by the 
posterior retractor-scar. Pallial line distinct. Dorsal muscle scars a few, lying 
in a line in the beak-cavity. 


MEASUREMENTS. 


No. Sex.| Length. Height Diameter. Beaks. Figure 

11...| o@ 40.5 mm. |24 mm. =59 pr. ct. of L..12 mm. =30 pr. ct.of L..at 11 mm. =27 pr. ct. of L. 

16...| co |43 Pr 27 = =6a ee oe 11 =26 re 

Serle ie seo | 130) 04 sf oe 11 oe a WOPISEXCRGNGV tips. 

29... .| co 162 “134 oD. 14 fo) st Pl. XXXIV, fig. 5. 
Ar el a Fees pe en ae (PI. XXXIV, fig. 7. 
eoea3| 2 (3 pon : = | Pl. XXXYV, fig. 1. 


Anatomy.—Anal opening slit-like, shorter than branchial opening, closed 
above; closed part about twice as long as open part, no supra-anal formed. Bran- 
chial opening separated from anal by a solid connection of the inner mantle-edges. 
Inner edge of anal almost smooth, that of branchial with distinct papille. In 
front of the branchial the mantle-edges are unconnected. Palpi subtriangular, 
a little longer than wide, their posterior margins connected at base. 

Gills long, the outer subtriangular, wider in the middle than the inner. The 
inner not triangular, wider than the outer anteriorly, its anterior end attached 
to the space between anterior end of outer gill and palpi, and in contact with the 
posterior base of the latter. Inner lamina of inner gill entirely connected with 
abdominal sae. 

Non-marsupial gills (Pl. XLV, fig. 1a) with few, scattered, irregularly dis- 
posed interlaminar connections. Marsupium (Pl. XLV, fig. 1b) located in the 
inner gills, occupying only a part of them, at and in front of the middle; at anterior 
end about one-fifth of the gill remains non-marsupial, and at the posterior end 
about two-fifths, so that the marsupium occupies two-fifths of the gill, the second 
and third from the anterior end. This location of the marsupium is constant for 


494 MEMOIRS OF THE CARNEGIE MUSEUM. 


the species (observed in seventeen females), with the only qualification that in 
young females the marsupium is smaller (less than two-fifths of the gill) but has 
a similar position. 

Marsupial part formed by interrupted septa (Pl. XLV, fig. 1b; Pl. XLVII, 
fig. 6). The arrangement into septa is distinct, but they are frequently inter- 
rupted, and their solid portions are short. In the middle of the marsupium they 
are at the utmost six to eight times as long as thick, and in its other parts they are 
very short. A distinet quincuncial (reticulate) arrangement is not seen. Toward 
the margin of the gill the septiform arrangement is again more distinct. 

The embryos fill the marsupium in an irregular mass, and the charged mar- 
supium, is moderately swollen. Placents are not formed. 

Glochidium (text-fig. 4b, p. 469, observed in six specimens) subtriangular, 
slightly oblique, anterior and posterior margins convex, converging to a point, 
anterior margin longer than the posterior. Hooks present, of the Hyriine type, with 
the S-shaped curve. L. 0.27 to 0.28 mm.; H. 0.27 to 0.28 mm.; L. of hook: 0.09 mm. 

It should be remarked that in one female the glochidia were immature, and 
no hooks could be seen; three females had only eggs, and one female was in the act 
of discharging. The dates of collecting, Jan. 26 and 29, should be recorded as 
showing the breeding season (midsummer of Southern Hemisphere). 

Remarks on the Specific Characters.—As will be seen from the descriptions 
of the following species, D. simillimus, D. vicarius, and D. decipiens are very closely 
allied to the present species in the shape of the shell; vicarius can be readily dis- 
tinguished by the biangular posterior ridge, and D. simillimus is a smaller shell. 
In other respects it is almost impossible to distinguish these species by the shell 
alone. The few obscure, differentiating characters will be pointed out below under 
the respective species. However, the investigation of the soft parts has shown 
that there are interesting differences chiefly in the location of the marsupium, In 
the present species, the marsupium is most fully developed, occupying a rather 
large part of the inner gills, slightly gravitating toward the anterior end. In the 
following species (chiefly simillimus and vicarius) it will be seen that this tendency 
is increased, and the marsupium becomes smaller, and is being shifted more dis- 
tinctly forwards (Compare pl. XLV, fig. 1b, with Pl. XLV, figs. 2b, and 3). It 
will also be seen that there are slight differences in the glochidia with regard to 
obliquity and size. 


ORTMANN: SOUTH AMERICAN NAIADES. 495 


9. DIPLODON SIMILLIMUS Ortmann, sp. nov. 


Shells: Pl. XX XV, figs. 38, 4, 5,6. Anatomy of gills: Pl. XLV, fig. 2. 
Glochidium: Text-fig. 4c, p. 469. 

Type-locality.—Rio Nhundiaquara, Morretes, Parans, Brazil (J. D. Haseman 
coll., January 3, 1909). Type-set: Carn. Mus. Cat., No. 61.9250. Thirty-two 
specimens with soft parts, males, barren and gravid females with glochidia. 

About a dozen additional specimens belonging to the same original lot have 
been studied. The locality is in a small coastal stream emptying into the Bay of 
Paranagua. 

No shells have ever been reported from the region of Paranagua Bay in Paranda. 
However, from a little less than one hundred miles to the south, in Santa Catharina, 
near Barra Itapocu (I believe that the Rio Itapoca, as given by Marshall, stands for 
this), Diplodon santamarie Simpson has been described (Simpson, 1914, p. 1270; 
and Marshall, 1917, p. 386, Pl. 52, fig. 6; Pl. 55, figs 1-4). This is founded upon 
three specimens only, and resembles our species to a degree. But judging from 
description and figures, it is somewhat larger (max. 63 mm.), longer (H. 52-59 
pr. ct. of L.), and the hinge has the posterior tooth of the left valve missing. Since 
nothing is known of the anatomy of D. santamarie, and the locality is not the same, 
it would be rash to unite our specimens with this species. 

Our species also is much like U. martensi Von Thering, and might fall under 
this according to Von Ihering’s conception. But it cannot be united with it on 
account of the different dimensions. While in martensi the height is said to be 
from 49 to 57 pr. ct., our specimens are mostly less elongated, with the height from 
53 to 66 pr. ct. of the length. In D. martensi the diameter is 32 to 35 pr. et., in the 
present species from 26 to 37 pr. ct. (this agreeing better with martensi than with 
imitator). But in the absence of exact localities for martensi and any knowledge 
of its anatomy, and in view of the general resemblance of all of these shells, it is 
impossible to identify our shell with any previously described, and no other alterna- 
tive exists, except to describe it as new. 

In the characters of the shell D. simillimus is very close to D. imitator. The 
description of the latter species would fit it very well, and I shall here only emphasize 
the distinguishing characters. 

1. D. simillimus is a smaller shell (max. length 61 mm., as against 80 mm. in 
imitator). 

2. The trapezoidal shape, with an angle between the upper and the posterior 
margins, is seen here only in very young shells. In older shells these two margins 
form a rather regular curve. 


496 MEMOIRS OF THE CARNEGIE MUSEUM. 


3. The lower margin of the shell of D. simillimus is frequently more nearly 
straight, so that the shell of older specimens appears more humped. 

4. Color of epidermis with hardly any green tints, but light to dark bronze- 
brown, in old shells brown-black. 

5. Pseudoeardinal teeth never stumpy, chiefly in left valve, but always com- 
pressed, although the two of the left valve and the posterior in the right are rather 
thick in old specimens. 


MEASUREMENTS. 


No. |Sex Length. | Height. Diameter. | . Beaks. Figured. 

5... 36.5 mm. 21.5 mm. =59 pr. et. of L.| 9.5 mm. =26 pr. ct. of L. at 8.5 mm. =23 pr. et. of L. 
DOS ANS KODE ae oe “ =61 < 11 =29 te 10 ei on 

18...) 9 | 42.5 22.5 =53) a 11 =26 ~ 95 “ =22 

11...) oc! | 45 27 =60 13 = 9 “ =20 Pl. XXXYV, fig. 3. 
233. 21 O59 39 =66 22 =f 14  =24 os 
22 |ole1  “ |37 =61 20.5 | [Sulla at pean ar peaee Pl. XXXV, fig. 5. 


The characters of the shells of this species are rather poorly marked, and can 
be ascertained only by the examination of extensive material. I have discovered, 
however, that there are important and constant differences in the anatomy. 

Anatomy.—Fully agreeing with that of D. imitator, but the marsupium is 
different (See Pl. XLV, fig. 2). It is located in the anterior part of the inner gill, 
entirely anterior to its middle, and extending forward to within a short distance 
of the anterior end of the gill, so that anteriorly less than one-tenth of the gill is 
non-marsupial, while posteriorly fully the posterior half of it is non-marsupial. 
The interlaminar connections form interrupted septa, but the septiform structure 
is less distinet than in D. imitator, and more of a reticulated (or irregular quin- 
cuncial) arrangement is evident. This structure of the marsupium is the same in 
all females investigated (altogether twenty individuals), and only in young ones is 
the marsupial part smaller. 

The Glochidium (Text-fig. 4c, p. 469) differs from that of D. imitator in being 
more distinctly oblique, and being longer than high. L. 0.28 mm., H. 0.24 mm. 
There are hooks of the same type, which are about 0.10 mm. long. 

My specimens were collected on January 3, which date indicates the breeding 
season, probably its middle, for eight females had only eggs, while nine had glochidia, 
in part not mature, and with the hooks yet unformed. 

The remarkable fact brought out by the study of the anatomy is that, while 
the species is extremely hard to distinguish from imitator by the shell, it has at least 
two anatomical characters (marsupium and glochidium), which are very well marked 


and constant. 


ORTMANN: SOUTH AMERICAN NAIADES. 497 


10. DrpLopon vicartus Ortmann, sp. nov. 


Shells: Pl. XXXYV, figs. 7, 8; Pl. XXXVI, figs. 1, 2. Anatomy of gills: Pl. XLV, 


fig. 3. Glochidium: Text-fig. 4d, p. 469. 


Type-locality—In creeks, Aqua Quente (eight miles from Iporanga), Sao 
Paulo, Brazil, tributaries of Rio Ribeira (J. D. Haseman coll., November 27, 1908). 
Type-set: Carn. Mus., Cat. No. 61.9251; fifteen specimens all with soft parts, 
males, barren and gravid females. 

Additional Locality.—Rio Ribeira, Iporanga, Sao Paulo, Brazil (J. D. Haseman 
coll., December 1. 1908). One specimen, male, with soft parts. 

Only one species of Diplodon has been described from the Rio Ribeira; this is 
D. mimus Simpson (1914, p. 1249; Marshall, 1917, p. 383, PI. 51, fig. 3) from Iguapé, 
Sao Paulo, at the mouth of the river. As has been pointed out above (p. 486), 
this species might possibly be D. granosus. But on the other hand a few particulars 
agree with the present species, as, for instance, the biangulation of the posterior 
end and the general resemblance to Elliptio complanatus mentioned by Simpson. 
Yet our shells cannot be this, because they are larger, less convex, and have dif- 
ferent dimensions. D. mimus is smaller (max. 45 mm.), and has, according to 
the measurements given, a considerably higher (60 to 76 pr. et.) and more swollen 
(D. 33 to 46 pr. ct.) shell, while D. vicarius has the height only from 52 to 63 pr. et. 
and the diameter from 26 to 31 pr. et., and is a good deal larger (L. 53 to 68 mm.). 
Of course, our form may fall under martensi Von Thering, but for the same reasons 
as in the case of the two preceding species, it cannot be called by this name, and 
thus we must describe it as new. 

It may perhaps be that D. vicarius, of which we do not know the beak-sculp- 
ture, is the older stage of the young specimens recorded from Iporanga as D. 
granosus (See p. 485). The shape and dimensions agree fairly well, but the size 
is very different, the maximum length of granosus being only 29 mm. and no inter- 
mediate specimens between these and minimum length of vicarius (53 mm.) are 
at hand. Thus the question must remain unsettled. D. granosus from other 
localities is also always much smaller than vicarius. 

This species is also extremely similar to D. imitator and D. simillimus. Yn size 
it stands between them (max. length 68 mm.). The outline is also subtrapezoidal 
or subelliptical, and the shell is quite compressed, resembling the shape of Elliptio 
complanatus of the United States. The lower margin in the shells before me is 
always rather straight, but I have not very young specimens. However, from the 
growth-lines it is seen that young shells must have had a gently curved lower margin. 
In none of my specimens is the beak-sculpture preserved. 


498 MEMOIRS OF THE CARNEGIE MUSEUM. 


Characters of the Shell—The description of D. imitator might also serve for 
this species. However, the following differences are noticeable: 

1. Posterior ridge of shell broad, and more or less distinctly biangulate, pro- 
ducing a biangulation also of the posterior end of the shell. This is the most 
striking character of the shell. In both D. imitator and simillimus the posterior 
end of the shell is evenly rounded without any trace of angulations. 

2. Epidermis not so shining as in the two other species, which is due to the 
development of additional fine concentrie wrinkles, which are irregular and best 
developed upon the posterior slope and near the lower margin. Upon the disk 
they form indistinct radiating lines (or narrow bands), which are obsolete in the 
two other species. Color of epidermis of vicarius lighter or darker brown, without 
green tints, and without bronzy lustre. 

The hinge-teeth are generally of the type of D. simillimus, 7.e., they do not 
become stumpy in old shells. They are, however, very variable, and much cut 
up, more so than in the two other species, and the posterior pseudocardinal of 
the left valve frequently is quite small or rudimentary. The nacre is whitish, but 
often inclines to lurid tints (purplish gray). 


MEASUREMENTS. 


Height. Diameter. Beaks. Figured. 


No. ISex.| Length. | 

: 
13...| | 53. mm.31_ mm.=58 pr. ct. of L./15.5 mm. =29 pr. ct. of L..at 12 mm. =23 pr. et. of L.| Pl. XXXV, fig. 7. 
9...| 9 | 63.5 “ 33.5 “ =63 os 14 =26 iW 12 “  =22 | Pl. XXXVI, fig. 2. 
10:2 3/9! 57 “34.5 “ =61 i: 16 28 MS) os, =20 - | 
1...| 9 | 58.5 33.5 =5i/ % 15 i 15 Sate 

o'| 67 35 =52 9 =23 ) “ =2 yyy 


| | Pl. XOEXVI, fig. 1. 


No sexual differences in the shell. 

Anatomy.—I have eight females, six of which are gravid; three with eggs, three 
with glochidia (immature in one). The structure of the soft parts is exactly as in 
the preceding species, except that of the marsupium (Plate XLV, fig. 3). As in 
D. simillimus, the marsupium is located in the anterior portion of the inner gill, 
anterior to the middle, but it occupies a still smaller part, and does not extend so 
near to the anterior end, and does not reach the middle of the gill. Anteriorly 
about one-ninth of the gill is non-marsupial, and posteriorly over half of it. The 
interlaminar connections are arranged in interrupted septa, the septiform arrange- 
ment being most evident anteriorly and in the middle of the marsupium, while 
posteriorly the arrangement is reticulate (indistinetly quincuncial). 

The glochidium (‘Text-fig. 4d, p. 469) is similar to that of D. simillimus, oblique, 
but slightly longer. L. 0.30, H.0.24mm. There are hooks of the same type, which 


ORTMANN: SOUTH AMERICAN NAIADES. 499 


are at least 0.09 mm. long. In one specimen with immature glochidia no hooks 
could be seen. 

In this case also the breeding season falls in the winter months of the northern 
hemisphere, but apparently a little earlier than in the other species (end of No- 
vember). 

Thus this species has anatomical characters of its own, chiefly observable in 
the size and location of the marsupium. It agrees most closely with D. simillimus. 


3. SPECIES FROM THE DRAINAGE OF THE UPPER PARANA. 


I have material belonging to the chilensis-group from the following tributaries 
of the Parana: Rio Iguassti, Rio Tieté, and Rio Grande in Sao Paulo. A form from 
the Iguassti is noticeably very closely related to the three species from the coastal 
streams just described. We should bear in mind that the head-waters of the 
Iguassu, from which this form comes, are in close proximity to those of the Rio 
Nhundiaquara and Rio Ribeira on the eastern watershed. 


11. DipLopoN DECIPIENS Ortmann, sp. nov. 


Shells: Pl. XXXVI, figs. 3, 4, 5, 6. Anatomy of gills: Pl. XLV, fig. 4. Section of 
gills: Pl. XLVI, fig. 7. Glochidium: Text-fig. 4e, p. 469. 


Type-locality— Creek, tributary to the Rio Iguasst, Serrinha, Paranda, Brazil 
(J. D. Haseman coll., December 23. 1908). Type-set: Carn. Mus. Cat. No. 
61.9253, thirteen specimens, males, barren and gravid females, all with soft 
parts. 

No Naiades have hitherto been known from the river-system of the Iguassu, 
and, as in the preceding species, none of the names of species which may occur here, 
ean be applied to our specimens with any degree of certainty. Therefore we in- 
troduce this form as a new species. 

In the shape of the shell this species is very close to the three preceding, es- 
pecially imitator and simillimus, which it resembles in its subelliptical or sub- 
trapezoidal outline. The latter shape is seen chiefly in younger specimens, while 
older ones become more subelliptical. The posterior ridge and the posterior end 
are never biangulate as in vicarius. In the glossy epidermis, D. decipiens also 
agrees better with imitator and simillimus, and the radial lines formed of fine 
wrinkles are poorly developed. The general description given for imitator might 
be repeated for this species, and the beak-sculpture in particular has the same 
character. Nevertheless the following peculiarities should be mentioned as 
diagnostic: 


500 MEMOIRS OF THE CARNEGIE MUSEUM. 


1. The beak-sculpture has a smaller number (ten to twelve) of radial bars, 
the bars having the same length (5 to 7 mm.) 

2. The outline of the shell is more frequently subelliptical, often rather regularly 
so, with both upper and lower margins almost equally curved. In some specimens, 
indeed, the lower margin is more nearly straight, but this never causes a distinctly 
humped shape (so often seen in simillimus). No trace of biangulation posteriorly. 

3. Epidermis in young shells bronzy-brown or bronzy-green; in older ones it 
becoming a deep chestnut-color, inclining partly to blackish. 

In size this species stands between imitator and vicarius (maximum length 
73 mm.). The relative dimensions are very much like those of the other three 
species. The hinge-teeth most resemble those of simillimus, never being stumpy, 
as in imitator; they are not much cut up; and the posterior pseudocardinal in the 
left yalve has a strong tendency to disappear, being sometimes entirely missing. 
The nacre is whitish, but generally lurid (purplish gray) in the cavity. 


MEASUREMENTS. 


Height. 


Length. 


No. |Sex. Diameter. | Beaks. | Figured. 
a...|o' | 26mm. |14.5 mm. =56 pr. ct. of L.. 6 mm. =23 pr. ct. of L.'at- 6.5 mm. =25 pr. ct. of L.| 

c OF poDu es 20:5 ** 59 Wane Ew ee) oy | Ulelsy I SPAN 2 Pl. XXXVI, fig. 6. 
3 2 | DS Boo) =56) y 18250, “= 32 - | 15 26) y Pl. XXXVI, fig. 5. 
4 op eee 4 36.5 =54 200i see — ol sg | 15 “ =22 oe Pl. XXXV, fig. 3. 
LOS | 70 38 ole 25 wi Sale pe 16 =23 Me 

aE ayer 40 =55 25 Set! : 16 ‘ -=22 3 Pl. XXXVI, fig. 4. 


No sexual differences in the shell. 

Anatomy.—Aside from three very young specimens, which probably are a male 
and two females, I have six males of good size, and one barren female, a gravid 
female with eggs, and two females with glochidia (in one of them immature). 

The anatomy is similar to that of D. imitator, simillimus, and vicarius, but 
the marsupium (Pl. XLV, fig. 4b) is quite different, essentially differing from that of 
the other species. It is located in the middle of the inner gill, leaving between one- 
fifth and one-fourth of the gill at the anterior end, and about one-third of it at the 
posterior end non-marsupial. Thus the marsupial portion is rather large, and more 
of it is anterior rather than posterior to the middle. This location comes nearer 
to what is seen in D. imitator, than in the other two species. The most striking 
character, however, which we have not before encountered, is that the interlaminar 
connections of the marsupial part are not interrupted, but form continwous septa, 
running from near the base of the gill close to the margin. These septa are heavy 
and stand very closely, forming regular, isolated water-tubes (See section on PI. 
XLVII, fig. 7). The whole of the marsupium has this structure, and no inter- 


ORTMANN: SOUTH AMERICAN NAIADES. 501 


rupted septa are seen anywhere. That these septa are only a modification of the 
scattered interlaminar connections is shown by the fact that the latter are found 
in the non-marsupial gills (See outer gill on Pl. XLV, fig. 4b, and gills of male, 
Pl. XLV, fig. 4a). All four of my large females show this arrangement, and in 
the two young ones traces of the beginning of this structure are seen. The em- 
bryos fill the water-tubes in loose masses, not forming distinct placentz. 

Glochidium (Text-fig. 4e, p. 469) much like that of D. vicarius, oblique, L. 
0.31, D. 24 mm., with hooks, 0.09 to 0.11 mm. long. One specimen has immature 
glochidia, but rudimentary hooks can be seen. The date of collecting (December 
23) gives a hint as to the breeding season. 

While this species is very close to the three preceding in the characters of 
the shell, it has differences in the soft parts, which are very striking. The structure 
of the marsupium is extremely interesting, and there is no doubt that it must be 
regarded at least as of specific value, representing a high specialisation of this 
organ. 


12. DreLopon pautista (Von Ihering) (1893). 


Anatomy of gills: Pl. XLVI, fig. 1. Section of gills: Pl. XLVIII, fig. 1; 
Glochidium: Text-fig. 4 f. p. 469. 


Unio paulista Von Txertna, 1893, p. 93, Pl. 4, fig. 7. 
Diplodon paulista Stupson, 1900, p. 873; 1914, p. 1229. 

Type-locality—Piracicaba, Sao Paulo, Brazil; according to Nehring (1893, p. 
166) in Rio Piracicaba Mirim. 

New Localities.—Rio Tieté, Mogy das Cruzes, Sio Paulo, Brazil (Headwaters 
of R. Tieté) (J. D. Haseman coll., July 19, 1908) males, barren and gravid females, 
originally twenty-five in the lot, all with soft parts. Rio Tieté, Sapina, Sao Paulo 


bo 


(Exact location unknown, but must be near city of Sado Paulo) (J. D. Haseman 
coll., July 23, 1908) one male with soft parts. Creek, tributary to Rio Mogy 
Guasst, Mogy Mirim, Sao Paulo, Brazil (tributary to Rio Grande and Paranda) 
(J. D. Haseman coll., August 7, 1908) males and gravid females, originally seven- 
teen specimens in the lot, all with soft parts. 

A detailed description of five specimens has been given by Von Ihering, but 
the specific characters have remained obscure. The specimens before me agree 
very well with this description, but it should be noted that the two forms of the 
shell supposed by Von Ihering to belong to the male and female, do not represent 
sexual differentiation, but simply individual variations. The more regularly 
ovate outline, believed to belong to the male, is in fact rather rarely well-developed, 


502 MEMOIRS OF THE CARNEGIE MUSEUM. 


while the other, somewhat more oblique, is more frequent; but both pass insensibly 
into each other. According to my material younger specimens are more apt to 
exhibit the more regularly ovate outline. 

This species is not very closely allied to those mentioned on the preceding 
pages, but represents a somewhat different type, and inclines towards the ellipticus- 
group by its often slightly oblique shell. It is much smaller than imitator, vicarius, 
and decipiens, and also does not attain the size of simillimus. The largest specimen 
before Von [herimg was 57 mm. long, while my largest falls even short of this (45 
mm. from Rio Tieté, 51 mm. from Mogy Mirim). The subtrapezoidal shape is only 
distmet in very young individuals; in larger specimens it becomes subelliptical or 
subovate, generally a little higher posteriorly and slightly oblique. The ground- 
color of the epidermis is greenish-olive, and never distinctly brownish, although old 
specimens may become blackish green. The beak-sculpture consists of fine, sharp, 
and short radial bars, the number of which is sixteen to eighteen, the median pair 
having a tendency to unite at the lower ends. 

The characters of the inside of the shell have been well described by Von 
Ihering. The left valve has generally only one pseudocardinal, but sometimes 
there is a trace of a second posterior one. It should be noted that, as described 
by Von Ihering, the posterior retractor-scar is separated from, and stands above 
the posterior adductor-sear, but not always, as in some eases it is connected with 
it, and this may be different, even in the right and left valve of the same individual. 


MEASUREMENTS. 


No. Sex. Length. | Height. Diameter. Beaks. 
Von Ihering... .. 48 to 57mm. 59 to 65 pr. et. of L. 31 to 35 pr. et. of L. 22 to 26 pr. et. of L. 
Mogy das Cruzes 
? 15.5 mm. 8.5 mm. =55 * 4 mm. =26 = at 4 mm.=26 x 

LS Aravs feet te) 27 ce 16 53!) 8 0) & 6 ‘ =22 oes 
LOK Se ow | 38 Ne 22 Fs 4 Gp ee sly) cS RD e s (=P 10) as 
2 weer svar 2 38 SS 24 Os) 4 14 Sor o 10 Si 6 a 

(SAG CEI fof 41 Ce 21GOM ee Ot 14  =34 i 10 “ =24 
LAY era ss fot 45 a 27 “ =60 ss 16 " =36 - 11 "== 24 sy 
Mogy Mirim 

ees ot |) 335) $65 WD GS) A } 14.5 ‘ =41 : 10 «  =29 s 
ee ote Oo 49 | 23.5 =60 13 co =a's} xf eae De apel = 
ee oc fr o 40:5: | 24 DS 15 Says a ' LD — 

YR fou 2 : 28 OF : (eS, | As 11.5 “ =27 ‘< 
Been 2 48 es 29 G0) u 16:55“ =34 13 =a ve 
Seeks | of 51 |, 82 “ =63 ‘ [1G S35 s 13 “ =26 os 


My two sets from the Rio Tieté and from a creek tributary to Rio Mogy 
Guassu, differ slightly from each other. In the former the size is a little smaller, 
and the young shells are rather more elongated, thus rendering the average height 
less. The diameter is also not so great in the shells from the Tieté. The measure- 


ORTMANN: SOUTH AMERICAN NAIADES. 503 


ments of the dimensions of the two sets largely overlap, and they agree very well 
with those given by Von Ihering. Of course, my material being more plentiful, 
the range of the dimensions is wider. 

An apparently allied form is D. suppositus Simpson (1914, p. 1245; Marshall, 
1917, p. 385, Pl. 51, fig. 2; Pl. 54, fig..1-4).1° The type is, according to Marshall, 
from “Paranda, Brazil,’ and other specimens are from Rio Tieté, Sao Paulo, and 
other localities in southern Brazil. This is also a comparatively small form, but, 
according to the measurements given, it is more elongated, the height being in 
the type 52 pr. ct. of the length (53 pr. et. according to Marshall), and in another 
specimen 58 pr. ct. This differs somewhat from our specimens (58 to 67 pr. ct.) 
and from Von Ihering’s paulista (59 to 65 pr. et). In addition suppositus has a 
chestnut-bronzy epidermis, while it is greenish in paulista. Thus the two forms do 
not agree. 

Anatomy.—I have investigated the soft parts of all of my shells, and there 
were altogether, aside from several small ones, where the sex could not be ascer- 
_ tained, nineteen males, six barren females, five gravid females with eggs, and seven 
gravid females with glochidia. 

The anatomy in general is like that of the genus Diplodon. But in this case 
again the marsupium (Pl. XLVI, fig. 1) in its size and location shows specific peculi- 
arities, exhibited by all of my females. It agrees with the preceding species in 
the fact that it occupies only a part of the inner gill, and in the slightly anterior 
location. But the marsupial part is very small, occupying about one-fifth or one- 
fourth of the length of the gill, leaving a considerable portion non-marsupial at 
the anterior end, and half or nearly half at the posterior end. The figure on PI. 
XLVI, fig. 1, represents a specimen with a rather small marsupium; generally it 
is a little larger. Thus the marsupium is in the middle of the gill, and slightly 
in advance of the middle. When charged, it forms here a rounded or oval swelling, 
rather distant from the base, and extending not quite to the edge. There is a 
slight variation in the specimens from the two main localities. In those from Mogy 
das Cruzes it is distinctly in front of the middle; in those from Mogy Mirim more 
median, but this difference is very slight and not always distinct. The inter- 
laminar connections form interrupted septa (also seen in the section, Pl. XLVIII, 
fig. 1), and there is no distinctly reticulate arrangement. 

Glochidium (Text-fig. 4f, p. 469) rather large, subtriangular, oblique, with 
hooks. L. 0.32, H. 0.27 mm.; hooks about 0.10 mm. long. (Thus the glochidium 
is slightly larger than in any of the preceding species.) 


16 The name suppositus was first given by Von Ihering (1893, p. 102) without description, from 
Rio Grande (Upper Parand, boundary between Sao Paulo and Minas Geraes). 


504 MEMOIRS OF THE CARNEGIE MUSEUM. 


4. Group oF Diplodon charruanus. 


Shell not compressed, but rather evenly convex and often considerably swollen 
when old. Outline subelliptical or somewhat subtrapezoidal, elongate, more 
or less poimted behind, straight, and not oblique. Beak-sculpture simple, with 
narrow, straight, uninterrupted bars, restricted to the region of the beaks. A 
few of these bars may be joined at their lower ends. 

The chief character by which this group is distinguished from that of chilensis 
is the absence of a flattening of the valves upon the sides. The valves are generally 
evenly convex, and in consequence of this, at least in larger specimens, the shell 
appears as more swollen. In other respects, the shelbis similar in outline and other 
characters, except that the posterior end is often produced into a distinet blunt 
point, which may be more or less elevated above the base-line. There is no dis- 
tinct tendency of the posterior portion of the shell to be higher than the anterior, 
and thus the shell is not oblique. A posterior ridge may be distinct or indistinct. 

The first species, D. parallelopipedon, (Lea) froms a transition toward the 
group of chilensis. 

The metropolis of these forms is in the system of the Rio de la Plata, but they 
are also found in the coastal streams of southern Brazil (Rio Grande do Sul). 


13. DIPLODON PARALLELOPIPEDON (Lea) (1834). 


Unio parallelipipedon D’Orsiany, 1848, p. 609; Corst, 1900, p. 447, fig. 30. 
Diplodon parallelipipedon Simpson, 1914, p. 1275. 

Unio parallelopipedon Von Martens, 1894, p. 164; Piuspry & Rusu, 1896, p. 30. 
Diplodon acutirostris (LEA) Simpson, 1914, p. 1276. 

Diplodon parallelipipedon and acutirostris HAaAs, 1913, pp. 22, 28, 52, 53. 

Type-locality—Rio Parana, Province of Corrientes, Argentina. 

Other Localities—Arroyo del Rosario, Uruguay (to La Plata) (D’Orbigny) ; 
Arroyo de las Vaceas, Uruguay (Corsi); Rio de la Plata, Colonia, Uruguay (Pilsbry 
& Rush); Rio Uruguay, Salto Oriental, Uruguay (Haas); Swamps of Rio Parana 
from Buenos Aires to above Corrientes, Argentina (D’Orbigny); Rio Paraguay 
(Von Ihering, 1893, p. 119); Paraguay (Von Martens); Rio de San Miguel, Prov. 
of Chiquitos, Bolivia, (D’Orbigny). 

The last locality deserves special attention, since it is in the Amazons-drainage; 
but it is in the most southern extremity of it, close to the divide toward the Para- 
guay. It certainly requires confirmation. 

New Localities—Rio Uruguay (in mud), Uruguayana, Rio Grande do Sul, 


ORTMANN: SOUTH AMERICAN NAIADES. 505 


Brazil (J. D. Haseman coll., February 5. 1909). One specimen, male, with soft 
parts. Pond along Rio Negro, Santa Isabel, Uruguay (J. D. Haseman coll., 
February 11. 1909). Four complete shells, and five isolated valves; of two of 
these soft parts, males. 

Distribution.—-Drainage of the Rio de la Plata from its mouth and its tributaries 
in Uruguay and southern Brazil up to the Rio Paraguay in Paraguay. Also reported 
as crossing the divide, and going into the headwaters of the Amazons in Bolivia. 
Not known from the Paranda above Corrientes. 

This is a species easily recognized by the elongated-subtrapezoidal shape, 
with the upper and lower margins nearly parallel, by the anterior position of the 
beaks, by the rather swollen shell and distinet (although rounded) posterior ridge. 
The sides of the disk are rather flattened, and in this respect this species resembles 
the chilensis-group, intergrading with it to a degree. My specimens are somewhat 
variable in shape, being longer or shorter. None of them shows the beak-sculpture, 
since the beaks are badly eroded in all, except in the specimen from Uruguayana, 
where they are only a little eroded, and consequently a little more elevated. But 
here also no beak-seulpture can be seen. It must occupy only a very short space 
near the beaks, hardly more than 5mm. The specimen from Uruguayana has the 
nacre suffused with red (already mentioned by D’Orbigny). 

There is not the slightest question that U. acutirostris Lea is an old, much 
eroded, and somewhat distorted specimen of this species. Haas has already sug- 
gested this. 

Anatomy.—I have only the soft parts of male specimens, but Lea has already 
described them in the ease of his D. acutirostris, and has furnished at least some 
information about the marsupium. 

Judging from my material, the anal opening is closed above without forming 
a supra-anal. Closed part over five times as long as the open, the latter slit-like, 
short, shorter than the branchial opening. Inner edge of anal indistinctly crenu- 
lated. Anal and branchial separated by a solid bridge, running a certain distance 
inward. Branchial with fine papillae, about three times as long as anal. Mantle- 
edges not united in front of it. Palpi subtriangular, lower margins convex, pos- 
terior margins connected for about one-fourth or one-third of their length. 

Gills long and rather narrow. In their posterior part they are of equal width, 
or the outer one is slightly wider; anteriorly the inner is much wider. ‘The outer 
is considerably narrowed anteriorly, its anterior end being situated near the highest 
point of the line of the attachment of the mantle. The inner gill has a straight 
margin in the middle, and anteriorly it is only slightly narrower, its anterior end 


506 MEMOIRS OF THE CARNEGIE MUSEUM. 


being immediately behind the palpi. Inner lamina of inner gills entirely con- 
nected with abdominal sac. Structure of the gills in the male as usual, but the 
interlaminar tissue is unusually well-developed, forming a rather thick layer 
chiefly on the inside of the primary limb of the gill; and it has, as usual, short, 
interrupted interlaminar connections, elongated in the direction of the gill-filaments, 
which in the middle of the gill are few and far apart, while they are a little more 
frequent near the ends. 

Lea describes the marsupium (of acutirostris) as occupying nearly the whole 
length of the inner gill, but no information is given as regards the finer structure. 

Color of foot brown or blackish in the distal part, otherwise the soft parts are 
whitish. 


14. DreLopon cHARRUANUS (D’Orbigny) (1835). 
Glochidium: 'Text-fig. 4g, p. 469. 


Unio charruana D’OrsrGny, 1843, p. 606, Pl. 71, figs. 8-11; Pinssry & Rusu, 1896, 
p. 81; Corst, 1900, p. 447, fig. 31. 

Unio faba (as form of charruana) D’OrBiaNy, 1843, p. 606 (text), as rhwacoica, 
Pl. 71, figs. 12-14 (in tabula per errorem, see Explanation of plates, p. 704). 
Unio rhuacoica D’OrsBiIGNyY, 1843, p. 606, Pl. 69, figs. 4, 5; Corst, 1901, p. 450, 

fig. 33. 
Unio aethiops Lea, Obs., X, 1868, Pl. 41, fig. 285 (jwv.). 
Unio parcus Lea, Obs., XII, 1869, Pl. 33, fig. 77 (juv.). 
Diplodon rhuacoicus, charruanus, ethiops, parcus, Sumeson, 1914, pp. 1242, 1243, 

1247, 1256. 
Diplodon hidalgot Haas, 1916, pp. 18, 49, Pl. 1, fig. 1. 
Diplodon parcus Haas, 1916, pp. 16, 49. 
Diplodon fortis MARSHALL, 1917, p. 382, Pl. 52, figs. 1-4. 

Type-locality—Small streams from Maldonado and Montevideo to Las Vacas, 
Uruguay (‘‘ Banda Oriental’’). 

Other Localities—Lake Potrero, Maldonado, Uruguay (Pilsbry & Rush); 
Rio Canelon Grande, Montevideo (D’Orbigny, rhuacoica); Dep. Canelones, Uru- 
guay (Corsi); Rio Miguelete, Uruguay (Haas, hidalgo’); Rio Negro, Tacuarembo, 
Uruguay; correctly $8. Fructuosa, on Rio Tacuarembo, tributary to Rio Negro 
(Marshall, fortis); Uruguay River (Lea, ethiops). 

New Locality.—Pond along Rio Negro, Santa Isabel, Uruguay (J. D. Haseman 
coll., February 11. 1909). About twenty-five specimens, seventeen with soft 
parts, including males and gravid females. 


ORTMANN: SOUTH AMERICAN NAIADES. 507 


Distribution.—Small streams of the “Banda Oriental” in Uruguay, from 
Maldonado westward, and also in the Rio Negro and the Rio Uruguay.!7 

An extremely variable form, of which I possess a good set from one locality, 
undoubtedly representing young and adult specimens of the same species, so that 
I am able to give a rather full account of it. It is very evident that different in- 
dividual phases have been previously deseribed as separate species. 

Characters of Shell—Shell of medium size (maximum length according to 
D’Orbigny, 70 mm.; my largest is 62 mm.), solid and rather heavy. Outline sub- 
trapezoidal, more or less elongated, straight (not oblique), but very variable. The 
upper margin may be rather straight (chiefly in young ones), or more or less curved 
(in older ones), with or without a distinct posterior upper angle. The posterior 
end of the shell is more or less pointed; the position of the point is variable, but 
generally rather low, and little elevated above the base-line. The lower margin 
is gently curved, often nearly straight in part (chiefly so in old shells), and never 
curved up suddenly in its posterior part, but only gently and gradually so, if at 
all. The posterior end of the shell is thus distinctly more tapering than the rounded 
anterior end, the posterior point lying rather low. The proportion of height to 
length of the shell is very variable, ranging from 48 to 65 pr. ct: 

Valves quite convex and swollen, hardly flattened upon the sides, but more 
convex anteriorly and over the posterior ridge, which is blunt, but more distinct 
towards the beaks (and in young shells). Diameter 34 to 50 pr. ct. of length. 
Beaks a little inflated, but not very prominent, located at 21 to 29 pr. ct. of length. 
Beak-seulpture seen only in my youngest specimens, extending not more than 8 
mm. from the point of the beak, consisting of about thirteen radial bars, of which 
only the lower ends are seen. They increase little in length posteriorly, are rather 
sharp in front, but the longest are somewhat obtuse, while the two last, right upon 
the posterior ridge, are again sharp and shorter. In some of my specimens, chiefly 
the younger ones, there are some short, oblique wrinkles (one to eight) upon the 
posterior slope; in others they are entirely absent. Lunula absent or present, 
narrow. 

Epidermis with numerous, irregular, finer and coarser, concentric lines; the 
finer ones sublamellar on posterior slope and towards the margin. Radial seulp- 
ture obscure, but present in the shape of fine lines, sometimes more distinct on 
the anterior portion of the shell. Color of epidermis dark olive-green to black. 

“ Von Ihering (1893, p. 102) reports athiops from the Guahyba drainage in Rio Grande do Sul, 


and a variety (piracicabana) from the Upper Parand-drainage in Sao Paulo, but these records should be 
doubted. 


508 MEMOIRS OF THE CARNEGIE MUSEUM. 


Old specimens are generally uniformly black; younger ones are dark greenish 
olive or brownish olive, sometimes with more or less distinct concentric lighter 
(brownish to yellowish) bands. 

Hinge-line gently or more strongly convex. Ligamental sinus over the pos- 
terior part of the lateral teeth; in larger specimens over the last fifth. Laterals 
rather straight in young, curved in older shells, one in right, two in left valve, 
their edges somewhat rough. Pseudocardinals normally two in right, and one in 
left valve, but often there is a second (posterior) one in the left valve. These 
teeth are extremely variable. In younger shells they are compressed and lamellar, 
directed obliquely forwards; the posterior tooth of the right valve is always thicker 
and higher than the anterior, and they are, chiefly the former, crenulated or denti- 
culated. In older shells, the posterior tooth of the right, and the (anterior) tooth 
of the left valve may become thicker, more stumpy, and may be much divided. 
The posterior tooth of the left valve, if present at all, may be larger or smaller, 
compressed or stumpy. . 

Cavity of shell and beaks moderate. Nacre in all my specimens white, iri- 
descent posteriorly. Anterior adductor-scar distinct and impressed; anterior 
retractor-sear separated from it, small and deep; anterior protractor-scar connected 
with it. Posterior adductor-sear less impressed, the posterior retractor-sear forming 
an upper process of it. Pallial line distinct. Dorsal muscle-sears a few, situated 
in the beak-cavity. 


MEASUREMENTS. 

No. | Sex. | Length. Height Diameter. Beaks. 
14. | og | 34 mm. | 20.5 mm. =60 pr. ct. of L. 12 mm. =35 pr. ct. of L. at 10 mm. =29 pr. ct. of L. 
12. fou | 48 os 26.5 =55 3g | 20) oA is 10 SrA = 
ce rol 54 Hs 35 =65 a 2h 30) Me 14  =26 . 
oe 2 2 54 is | 30.5 =56 | 24 4 rs 13  =24 : 
Half shell... . . .| 58 Gs | 3l =53 + ee One — 3) 3 13 OC =D ~ 
3.. Q | 61 HalesD =57 S ek A Se xs 17.5 ‘ =29 5 
2 | 62 ‘= | 35 =56 2h SS =44 si | 15 “ =24 - 

For comparison I give here previous measurements. 
Length Height. | Diameter. Beaks. 

charruanus, D’Or- 

bigny’s text: 70 mm. 61 pr. ct. of L. | 45 pr. et. of L. 
rhuacoicus, D’Or- 

bigny’s text: | 63° mm. 51 pr. ct. of L. 43 pr. et. of L. 
faba, (rhuacoicus), | 

D’Orbigny’s fig. 43 Se 20.5 mm. =48 ee 15 mm. =35 = 12 mm. =28 pr. ct. of L. 
athiops, Lea's fig. | 53 2 28 oe 18 =34 2 “es bs 
parcus, Lea’s fig. 36 “ 18 >i) 13 =36 10 =28 4 
hidalgoi, Haas: 63 *e 39 “« =62 ai, 43 

66.5 42 =63 2 AL 


fortis, Marshall: 66 a y 37 . 


ORTMANN: SOUTH AMERICAN NAIADES. 509 


Remarks. 


Among our specimens the single valve comes nearest to the measure- 
ments given for U. rhuacoicus. D’Orbigny himself admits that this may be only 
a more elongated form of charruanus, and his faba, united by him with charruanus, 
is even more elongated. There is no reason for keeping rhuacoicus separate, since 
the proportional length is said to be the only difference. 

The variations in the shape of the shell are, indeed, very great. Younger 
specimens are, however, more uniform; they are more elongated, and their normal 
shape is well rendered in D’Orbigny’s figures of faba (Pl. 71, figs. 12-14), and in 
the figures of wthiops and parcus. The latter undoubtedly is a young shell, but 
ethiops also belongs here. Specimens like those measured under Nos. 12 and 9 
resemble this very much, except that they are a little more swollen, and our smallest 
(No. 14) looks very much like parcus, but it is less elongated. 

In the description and the figures of D’Orbigny only the color of the epidermis 
is not exactly as in our specimens. D’Orbigny describes it in charruanus as well as 
rhuacoicus as brownish green, and ‘figures it as lighter or darker brown, while the 
color of faba (Pl. 71, figs. 13, 14) is blackish, agreeing better with our specimens. 
However, our young specimens have a color, which may be called brownish green, 
or rather ‘“‘olive-brown.” Lea’s wthiops is said to be black. 

The chief characters of this species thus seem to be the subtrapezoidal, rather 
elongate, straight shell, with a moderately sharp posterior point, located only 
little above the base-line; the somewhat swollen shell, with a moderate and blunt 
posterior ridge, and the brown to blackish color of the epidermis. The chief varia- 
tions are found in the length of the shell, and the somewhat higher or lower position 
of the posterior end. 

There is no question that hidalgoi Haas and fortis Marshall are this species. 
The former is founded upon two specimens, the latter upon a single one, which 
certainly represent individual phases. Specimens greatly resembling these are 
among my material. 

Anatomy.—I have the soft parts of eleven males and six gravid females, three 
with eggs, three with glochidia, one of these discharging. 

Anal opening slit-like, closed above, the closed part about four times as long 
as the opening; the latter shorter than the branchial opening. The two openings 
are separated by a solid mantle-connection. Branchial with small papillze. Palpi 
subtriangular, their posterior margins connected near the base. Gills posteriorly 
of about the same width, but anteriorly the inner is wider, and its anterior end is 
immediately behind the palpi. Inner lamina of inner gill entirely connected with 
abdominal sac. Non-marsupial gills with scattered, short, interlaminar connec- 


510 MEMOIRS OF THE CARNEGIE MUSEUM. 


tions. The marsupial part of the female occupies a large portion of the inner gill, 
leaving about one-fourth of the gill free in front, and a smaller part free behind, 
thus gravitating slightly toward the posterior part of the gill. The interlaminar 
connections could not be distinetly observed by me on a lateral view, since no barren 
females are at hand; but from sections it was possible to infer that they form in- 
terrupted septa forming a system of intercommunicating water-tubes. The eggs 
and glochidia fill the water-tubes and the perforations of the septa in a mass, which 
is not conglutinated and divided into placente. 

The glochidium (Text-fig. 4g, p. 469) has the characteristic triangular shape, 
somewhat oblique, with the point situated below the posterior end of the upper 
margin (like the figure of the glochidium of U. peculiaris, See Lea, Obs. XII, 1869, 
Pl. 34, fig. 80). This point does not possess a hook. Size of glochidium: L. 0.31, 
D. 0.26 mm. 

I have examined the glochidia of three specimens; one of these had the mar- 
supium largely empty, and thus it appears to have been discharging. Yet no hooks 
were seen. But it may be that the discharge in this case was premature, that 
none of the glochidia were mature, and that the hooks might have developed later. 
This can be decided only by investigating more material. 


15. DreLopon picreus (Lea) (1860). 
Anatomy of gills: Pl. XLVI, fig. 2; glochidium: Text-fig. 4h, p. 469. 
Unio piceus Lna, Obs., X, 1863, Pl. 41, fig. 287. 
Diplodon piceus Simpson, 1914, p. 1244; Haas, 1916, pp. 15, 49. 

Type-locality.— Uruguay River. 

Other Localities—Rio Uruguay, Salto Oriental, Uruguay (Haas); Rio Migue- 
lete, Uruguay (Haas). 

Localities Represented in the Carnegie Museum.—Rio Uruguay (in mud), 
Uruguayana, Rio Grande do Sul, Brazil (J. D. Haseman coll., February 5, 1909) 
eight specimens, seven of them with soft parts, males and gravid females. Arroyo 
Miguelete, Montevideo, Uruguay (J. D. Haseman coll., February 17,1909) one 
specimen. 

Distribution.—Positively known from the Uruguay River, and from a small 
coastal stream (R. Miguelete) near Montevideo, and probably more widely dis- 
tributed in the ‘‘ Banda Oriental” in Uruguay. It possibly may be only a form of 
charruanus. Corsi does not mention it from Uruguay. 

A species closely allied to D. charruwanus, and very near to it in its dimensions, 
except that it does not show the same extremes of variation. It is, however, 


ORTMANN: SOUTH AMERICAN NATADES. 511 


shorter on the average (H. 59 to 63 pr. et. of L., while D. charruanus varies from 48 
to 65 pr. ct.). In addition D. piceus is not so subtrapezoidal in outline, but rather 
subovate, which is brought about by a stronger curve of the lower margin, which 
ascends much more distinctly posteriorly, so that the posterior end of the shell is 
more elevated above the base-line. At the same time the posterior end is rather 
blunt and rounded, and not so pointed as in D. charruanus. 

All other characters of the shell are similar to D. charruanus. The radial 
sculpture of the epidermis is more distinct. The inside of the shell is also similar, 
but the pseudocardinals are simpler, always elongate and compressed, and there is 
always only one in the left valve. They are not much cut up, but only crenulated 
and rugose. Nacre white, though one of my specimens has purplish blue in the 
cavity, probably a discoloration. 

Beak-sculpture, as far as can be seen in smaller shells, similar to that of D. 
charruanus. But there is a very small specimen, which is only 10 mm. long, among 
them, which is doubtfully referred here. In this ease the sculpture consists of 
fifteen radial bars, of which the eighth and ninth unite at their lower ends. The 
anterior bars are shorter, but there is not much difference in this respect from the 
posterior bars. The bars are rather sharp and fine, but those upon the umbonal 
ridge are slightly thicker, and the two last, upon the posterior slope are very fine 
and shorter. 


MEASUREMENTS. 


No. | Sex. | Length. Height. | Diameter. Beaks. 
F | 


Mode 2 es 2 | 30 mm. 19 mm. +63 pr. ct. of L. 11.5 mm. =38 pr. et. of L. at 8.5 mm. =28 pr. ct. of L. 
pen oe | 2 | 35 #3 PAU RSs 53!) MS 13 aoe rs 10 29 3 
Bie uel ro ill acy! Ye 31 ae Or ~ 21 AL " 15 Se =29 
Bteret hes 2) || era ES 30 os * | 20.5 =40 wf 15 =) =29 
CRIS ote Ore GAs son! Ee Ate) “ 28 se ‘ Cos 
Montevideo. 
57 * SOF 25.5 =45 16 FS 
Lea’s fig. | 47 * 28 50), ay | 19 10 12 ey “ 


Remarks.—There is not the slightest doubt that my specimens represent the 
U. piceus of Lea, but the question of its possible identity with D. charruanus must 
be left undecided, also that of other possible synonyms (lepidus Lea, and firmus 
Lea). I cannot unite these for the present on account of certain peculiar structures 
in the anatomy, which will be pointed out presently. 

Anatomy.—I have the soft parts of one male, one barren female, and five 
gravid females, three of the latter with eggs, and two with glochidia, but in one 
only are the glochidia mature. 

The structure is entirely like that of D. charruanus. With regard to the mar- 


512 MEMOIRS OF THE CARNEGIE MUSEUM. 


supium (Pl. XLVI, fig. 2) it is to be remarked that it occupies in larger specimens 
a somewhat greater portion of the inner gill, leaving anteriorly as well as posteriorly 
less than one-fourth of the gill free. In smaller females the marsupial part is 
relatively smaller. The interlaminar connections form distinct; but interrupted, 
septa. The connections stand very close, and the septiform structure prevails 
throughout the marsupium, and very little is seen of a transverse or reticulate 
arrangement. In some parts, chiefly towards the margin, the septa become more 
or less continuous. Thus there are here rather distinct, but intereommunicating 
water-tubes (ovisacs), which are filled, when charged, with masses of eggs connected 
with each other through the communications, so that no placenta-like arrangement 
is observed. 

Glochidium (Text-fig. 4h, p. 469).—Higher and more upright than that of D. 
charruanus; L. and H. about the same, 0.28 to 0.29 mm. Thus it is more like that 
of D. firmus figured by Lea (Obs., XII, 1869, Pl. 34, fig. 82), but not quite as upright. 
At the point of the lower margin there is a hook of the usual shape, about 0.09 mm. 
long. But such hooks are present in only one of my specimens, in the other the 
glochidia are too immature. 

It would be quite remarkable if in two species, so closely allied as D. charruanus 
and piceus, the glochidia should differ so fundamentally, that in one there are 
hooks, and in the other not. But judging from my material, this is the case. How- 
ever, it must be emphasized again that my material is scanty, and possibly in the 
ease of D. charruanus I do not at all have ripe glochidia. 


16. DrpLODON URUGUAYENSIS (Lea) (1860). 


Unio uruguayensis Lma, Obs., X, 1868, Pl. 45, fig. 298. 
Diplodon wruguayensis Simpson, 1914, p. 1234. 
Unio apprimus LEA (1866), Obs., XII, 1869, Pl. 33, fig. 78. 

Type-locality— Uruguay River. 

New Locality.—Pond along Rio Negro, Santa Isabel, Uruguay (J. D. Haseman 
coll., February 11, 1909). Five complete specimens, and several odd valves, 
two specimens (male and female) with soft parts. 

Distribution.—Iknown only from Rio Uruguay and Rio Negro. 

The synonymy and affinity of this species is obscure. Simpson thinks that it 
is close to D. wymani, but the latter is a compressed shell, while wruguayensis is 
much swollen. U. apprimus also is a swollen shell. Lea has already suggested 
that this is close to uruguayensis, but that it differs chiefly in the hinge-teeth, 


ORTMANN: SOUTH AMERICAN NAIADES. 513 


which are more lamellar and compressed in the latter (a smaller shell), and more 
stumpy and cut up in apprimus. My material shows that the character of the 
hinge-teeth changes with age. In general my specimens correspond in size and 
shape to uruguayensis, but the larger ones have more stumpy teeth, and thus I 
believe that apprimus is an old specimen of uruguayensis. Both Simpson and 
Haas (1916, p. 12, 47) unite apprimus with wymani, which cannot be correct on 
account of the difference in obesity. I think wymani belongs to lacteolus (See 
below). 

However, it is quite possible that all these forms are variations of one and 
the same species, and then, of course, our general arrangement must be changed. 
As regards the present form I can only say that it looks like a very large and heavy 
charruanus, the shell being rather elongated, subtrapezoidal, and much swollen. 
In lacteolus, the shell is higher and more ovate, and much more compressed. In 
none of my specimens is the beak-sculpture seen. 


M®8ASUREMENTS. 

No. Sex. | Length. Height. | Diameter. Beaks. 
Ostepereiete | 73° mm. | 50 mm. =68 pr. ct. of L. 31 mm. =43 pr. ct. of L. at 19 mm. =26 pr. ct. of L. 
eo ees ee f WS.) >: 47 et iy! a 37.“ =50 s 2 Oe = 
Dee ae ache | 52“ =67 Aes ol Die =2i, 
VE he hte Oe gs: My | 52 Cds oa ao ae = 19, “ =24 P 
(Gee sored 79 aia 60 Me Sarasa ms 20 oe) 
uruguayensis..... 70 | 45 4. ¥ |} 30 “ =43 me 
apprimus'®....... 101 66 “ =65 re | 40 “ =40 


Anatomy.—Soft parts of a male and a barren female at hand. 

Color of soft parts: distal part of foot dark gray, this color sharply marked off 
from the whitish basal part. 

Anal closed above; closed part about four times as long as the open part, 
which is slit-like, and shorter than the branchial, and separated from it by a solid 
mantle-connection. Branchial opening with small, but distinet, papillae. Palpi 
rather large, subtriangular, with lower margins strongly convex; posterior margins 
connected at base. 

Gills long and moderately wide, the inner one much wider than the outer 
anteriorly, its anterior end immediately behind the palpi. Inner lamina of inner 
gill entirely connected with abdominal sac. Non-marsupial gills with scattered, 
short, interlaminar connections. In the female a large section of the inner gill 
is marsupial, about one-fourth of the gill remaining non-marsupial at the anterior 


18 The measurements of uruguayensis and apprimus are those given by Simpson for the respective 
types. Those for apprimus are given by him under wymani (p. 1231). 


514 MEMOIRS OF THE CARNEGIE MUSEUM. 


end, and less than that at the posterior end. The interlaminar connections of the 
marsupium are developed as interrupted septa, forming communicating water- 
tubes. The connections are short, and are also arranged in irregular cross-rows; 
but towards the edge of the gill, the septiform arrangement is quite distinct. 


17. DreLopon HILDA Ortmann, sp. nov. 


Shell: Pl. XXXVI, fig. 7; Pl. XX XVII, figs. 1, 2, 3; Anatomy of gills: Pl. XLVI, 
fig. 3; Glochidium: Text-fig. 47, p. 469. 

Type-locality—Rio Jacuhy, Cachoeira, Rio Grande do Sul, Brazil (J. D. 
Haseman coll., January 26, 1909). T'ype-set: Carnegie Museum, No.. 61.5864. 
Fourteen specimens, males, barren and gravid females, soft parts of all in aleohol. 

There were six additional specimens in the original lot. 

Description of the Shell.—Shell rather small (maximum length 46 mm.), rather 
solid. Outline subelliptical or indistinetly subtrapezoidal, height 57 to 63 pr. ct. 
of length. Upper margin straight or gently convex, forming a blunt angle with 
the posterior margin. Posterior margin obliquely descending, straight, or gently 
convex, forming a blunt point with the lower margin; this point situated distinetly 
above the base-line. Lower margin rather regularly convex, ascending anteriorly 
and posteriorly, its lowest point situated between beaks and posterior end of 
ligament (rather median). Anteriorly the margin is regularly rounded. Anterior 
end of shell not much narrower than the posterior, which tapers to the blunt pos- 
terior point, so that the shell is rather regularly elliptical, with the posterior end 
subpointed, the angle of the posterior upper margin giving a suggestion of the 
subtrapezoidal shape. 

Valves rather regularly convex, greatest diameter slightly behind the middle, 
but distinetly in front of the posterior ridge, which is very blunt and broad. Pos- 
terior slope somewhat compressed, sometimes with a trace of a radial furrow. 
Sides of disk less convex, but not at all flattened. Diameter 34 to 44 DE Gt: Of 
length, so that the shell appears as moderately swollen. Beaks a little inflated, 
but not very prominent above the hinge-line, located at 23 to 28 pr. et. of the 
length. Beak-sculpture seen only in the smallest specimens, and only the lower 
part of it. There are about fourteen radial bars, the anterior rather sharp, the 
posterior located just in front of the posterior ridge, broader (at least their lower 
ends) and the latter are a little longer than the former. The last two or three 
bars are again finer and shorter. The longest bars are about 8 mm. long. There 
may be fine, short, oblique wrinkles upon the posterior slope, but these are distinet 
only in a few specimens. Lunula short, very narrow, or practically absent. 


ORTMANN: SOUTH AMERICAN NAIADES. 515 


Npidermis shining, chiefly so in the middle of the disk and in younger speci- 
mens, but with unequal concentric wrinkles and striaw, which become somewhat 
sublamellar on the posterior slope and near the margins. Radial sculpture present, 
consisting of irregular, often Beuiem ated lines, chiefly upon the anterior part of 
the shell, often appearing as “scalariform stripes’’ (radial rows of fine, short, con- 
centric wrinkles). Color i epidermis light to dark brown; in young specimens it 
is a beautiful, shining, golden brown, lighter in the middle of the shell and towards 
the beaks (and sometimes here with light greenish shades). In older shells the 
color is chestnut-brown to dark brown. In some specimens there are indications 
of darker concentrie bands. No traces of color-rays, except one or two very faint 
dark rays upon the posterior slope (seen only when held up against a strong light). 

Hinge-line very gently curved. Ligamental sinus over the posterior fourth or 
third of the lateral teeth (more posterior in old shells, which shows that the ligament 
is comparatively longer in them). Lateral teeth gently curved, long, one in right, 
two in left valve, finely rugose. Pseudocardinals obliquely direeted forward and 
downward, normally two in right, one in left valve, compressed, but not very 
long, their edges crenulated and serrated. The posterior in the right valve more 
elevated than the anterior, and often thicker. Sometimes there is a trace of a 
second posterior tooth in the left valve, but this is always small. 

Cavity of shell and beaks moderately deep. Nacre whitish, shining g, in the 
largest specimens the thickest parts (toward the front of the shell) have a faint 
rosy hue. Musele-scars of the typical shape; the anterior adductor-scar is rather 
deep, the retractor-scar separated from it, round and deep, the protractor-sear 
connected with it; the posterior adductor- and retractor-sears are united.  Pallial 
line distinct. An irregular, longitudinal row of dorsal scars in the beak-cavity. 


M®ASUREMENTS. 

No. Sex.| Length. m | Height. | Diameter. Beaks. Figure a. 

(hes Z ae mm. 114.5 mm. =58 pr. et. of L,| $8.5 mm. =24 pr. ct. . of Ib lat 28 pr. ct. of L.| Pl. XX XVII, fig. 1. 
(ope © /19.5. Ot) i eb“ s==S5, Us re 

Rests : 23.0 ““ =63 . Spee =A i 

p...| 2 | ane “124 aa 00) 5 16.5 “ =44 ;: ? 

q a | 43 ie 24.5 CO Sei - \17 *=40 ye Pl. XXXVI, fig. 7. 
UBeeriee: le 40ro. eee 27. was Bs l19 AT at e Pl. XXXVII, fig. 2. 


Remarks.—I have been unable to recognize this species in any of the published 
descriptions. It is a rather beautiful shell; marked by its small size, ne: arly 
regularly elliptical outline, with no obliquity, rather swollen valves, and with a 
peculiar, shining, golden brown color when young. It resembles, to a degree, 
D. charruanus, but differs from it chiefly in size, more regular shape, and the gloss 
of the epidermis. 


o 
—_ 
or) 


MEMOIRS OF THE CARNEGIE MUSEUM. 


Very few species of Diplodon are known in Rio Grande do Sul, from the drainage 
of the Guahyba (to which the Rio Jacuhy belongs)and all have been only incident- 
ally mentioned by Von Ihering (1893). Under U. ethiops piracicabana (I. ¢., p. 
102) he reports that U. e@thiops is found in the Guahyba River. I have been unable 
to discover this species, which is identical with charrwanus, in the material col- 
lected by Haseman in this system, and I am sure that the present form is not the 
one which Von Ihering calls wthiops. From his casual remarks it is seen that the 
latter has a shallow depression on the disk (J. ¢., p. 104), and nothing of the kind 
is seen In D. hilde. 

Anatomy.—I have two barren females, and three gravid females with glochidia. 
Of the latter, one had only very few glochidia in the marsupium, but some were 
in the suprabranchial canals, and thus it was evidently discharging. The rest 
of my specimens are males. 

Color of soft parts whitish; distal part of foot grayish black. 

Anal opening closed above; closed part about four times as long as the open 
part, the latter slit-like, slightly shorter than the branchial; the latter has small, 
but distinet papille. Anal and branchial openings separated by a solid mantle- 
connection. Palpi moderate, subtriangular, posterior margins connected at base. 

Gills long and rather wide. They are about equally wide posteriorly, but the 
outer is subtriangular and narrows anteriorly, while the inner does not, and re- 
mains as wide as posteriorly, with its anterior end immediately behind the palpi. 
Inner lamina of inner gill entirely connected with abdominal sac. The non- 
marsupial gills with scattered interlaminar connections. In the female, the mar- 
supium (Plate XLVI, fig. 3) is located in the inner gill, but anteriorly about one- 
third of the gill remains non-marsupial, posteriorly much less, about one-fifth of 
it or less, so that the marsupial part is located distinctly more backward in the 
gill, occupying about half of its length. When charged, the marsupium forms a 
slightly swollen patch. In young specimens the marsupium is smaller. Inter- 
laminar connections in the marsupium forming septiform rows, with a tendency 
to fall also into irregular transverse rows. The transverse arrangement prevails 
near the base and in the middle of the gill, here and there with a suggestion of a 
quincuncial disposition; the septiform arrangement is found toward the margin 
of the gill. 

Glochidium (‘Text-fig. 47, p. 469) subtriangular, longer than high, with a ventral 
point, slightly oblique, the point being vertically under the posterior end of the 
upper margin. There are no hooks. In one of my specimens, the glochidia are 
not margined (not mature); in the two others they are margined, with a narrow 


ORTMANN: SOUTH AMERICAN NAIADES. S17 


rim around the anterior-lower-posterior margin, representing, apparently, the first 
rudiments of the postembryonal shell. Size (without rim): L. 0.29 to 0.30; H. 
0.26 mm.; (with rim): L. 0.34 to 0.35; H. 0.28 to 0.29 mm. 

The hookless glochidium, provided with a rim or margin, is highly interesting 
in view of the fact, that this structure has not been observed in other species of the 
charruanus-group. 


5. Group oF Diplodon lacteolus. 


Like the fourth group (that of charrwanus), but shell higher and shorter, 
subtrapezoidal to ovate, chiefly so when young, compressed or somewhat swollen. 
Beak-sculpture fine or a little heavier and better developed, but not covering a 
large part of the shell. 

This group stands close to that of D. charruanus. The greater height of the 
shell is chiefly evident in the young shell, which may be slightly oblique. But 
the older shells are also shorter and higher than in the species of the charruanus- 
group, although they generally are less elevated than younger shells. They are 
not oblique, and have a rather regular, broadly ovate, or subelliptical outline. 


18. DipLopon BURROUGHIANUS (Lea) (1834). 
Anatomy of gills: Plate XLVI, fig. 4. 


Umio burroughianus Lea, Obs., I, 1834, Pl. 10, fig. 27; D’OrBriany, 1843, p. 609; 

Von Martens, 1894, p. 164; Corsi, 1901, p. 450. : 

Diplodon burroughianus Stimpson, 1914, p. 1271. 

Type-locality—Rio Parana, Province of Corrientes, Argentina. 

Other localities.—Small rivers of the Banda Oriental in Uruguay (D’Orbigny); 
Montevideo (D’Orbigny); swamps along the Parana from Buenos Aires to above 
Corrientes (D’Orbigny); Paraguay (Von Martens). 

It also occurs near Santa Cruz de la Sierra in Bolivia (D’Orbigny) which is 
in the drainage of the Amazons. 

New Locality —Pond near the Rio Negro, Santa Isabel, Uruguay (J. D. Hase- 
man coll., February 11, 1909). Three complete specimens, two of them, male 
and female, with soft parts, and four odd valves. 

Distribution.— Drainage of Rio de la Plata, including the small streams of the 
Banda Oriental, Rio Negro, and the Parana and Paraguay to Paraguay, and possibly 
also in the Amazon-drainage in Bolivia. The latter part of the range, however, 
should be confirmed. 

Some of my specimens, chiefly the female with soft parts, agree very well with 


518 MEMOIRS OF THE CARNEGIE MUSEUM. 


burroughianus in shape, dimensions, and color. Others differ more or less, chiefly 
in having the posterior point of the shell less elevated above the base-line. Thus 
they approach other species described by Lea as piger (1860) and ampullaceus 
(1869), both from the Uruguay River (See also ampullaceus, Haas, 1916, pp. 11, 
47). My material is not sufficient to work out the synonymy. 


MEASUREMENTS. 


Sex. Length. | Height. | Diameter. | Beaks. 


.e) 54 mm-| 38 mm.=70 pr. ct. of L. | 23.5 mm. =44 pr. ct. of L.) at 18 mm. = 24 pr. ct. of L. 
fot DG:0) Ja OOM ue Ihe : Lie a — 9, as LO ey Hoth 
60 “ | 44 = {33 st 26 a 43 a 16 “ =27 “(Lea’s figure) 
100 ee 62 LG 44 LG (D’Orbigny) 
94 OD |G 4e aos UL | 40 = A3 E (Von Martens) 
S85 2h N58 okeee—nb S (Bomeeo—A0 xt (Simpson) 
eae SS Ube Si . 263i a Do. 


The two specimens measured by Simpson do not include the type. They are 
more compressed than any others. 

Anatomy.—The soft parts of a male and a female are at hand. 

Color of soft parts whitish, distal part of foot grayish. 

Anal opening slit-like, closed above, short, shorter than the branchial opening, 
separated from the latter by a connection of the mantle-margins. Branchial 
opening short, its inner edge with small, but distinet papillae. Palpi subtriangular, 
moderately large, lower margins convex, posterior margins united at base for a 
short distance. 

Gills of the usual shape; the inner the wider, chiefly in front, its anterior end 
close behind the palpi. Structure of non-marsupial gills as usual. Marsupial 
portion in the female (Pl. XLVI, fig. 4) located in the inner gill, leaving about one- 
third at the anterior end, and about one-fifth at the posterior end free, so that the 
marsupium distinctly gravitates toward the posterior part of the gill. Interlaminar 
connections arranged in interrupted septa, and irregular, transverse rows, here 
and there quincuncial. This irregularly reticulate structure prevails throughout 
the marsupium, and the septiform arrangement is obscure. 


19. DipLopoNn LAcTEOLUS (Lea) (1834). 


See: Diplodon lacteolus (Lea) and D. wymani (Lea) (1860) Stmpson, 1914, p. 1226, 
1230.!° 

19 Lea himself (1834, p. 90) has identified the type of Lamarck’s U. delodonta (1819) with his lacteolus 

(1834, p. 40), but not until after the latter name had been published in a satisfactory way, while the 


original description of delodonta is absolutely unidentifiable. Thus, according to the rules, lacteolus 


must be used, as Simpson has done. 


ORTMANN: SOUTH AMERICAN NAIADES. 519 


The following references should be added to those given by Simpson. 

Unio delodonta D’OrsBiGNy, 18438, p. 605; Corsi, 1901, p. 449. 
Diplodon wymani Haas, 1916, pp. 12, 47. 

As to the synonymy compare Simpson. His D. wymani only in part belongs 
here. D. apprimus Lea, united by him with wymani, is different (more swollen, 
see above p. 512). On the other hand, I cannot distinguish the real wymani from 
lacteolus, and Von Thering (1893, p. 117) also unites them. 

Type-locality.—Rio de la Plata. 

Other Localities.—Stream, Villa del Cerro, Montevideo, Uruguay (D’Orbigny) ; 
Rio Uruguay (Lea, wymani); Rio Uruguay, Las dos Hermanas Islands, Uruguay 
(D’Orbigny); Rio Uruguay, Salto Oriental, Uruguay (Haas); Rio San Salvador 
(trib. to Uruguay), Soriano, Uruguay (Corsi); Buenos Aires (D’Orbigny); Rio 
Batel and Rio Corrientes, Province of Corrientes, Argentina (D’Orbigny). 

New Localities—Pond near Rio Negro, Santa Isabel, Uruguay (J. D. Haseman 
coll., February 11, 1909). One specimen, young. Brooklet, two miles north 
of the City of La Plata, Argentina (Dr. W. J. Holland coll., September 24, 1912). 
Two specimens. 

Distribution.—Lower La Plata and Parana systems, upward to the province of 
Corrientes; also in the lower Uruguay and Rio Negro, and small tributaries of the 
La Plata in Argentina and Uruguay. 

My specimens from La Plata are typical. The young specimen from Santa 
Isabel is interesting in having a rather high shell, which is slightly oblique, but 
comparison with the other specimens shows that, according to the growth-rests, 
the latter had the same shape when young. This young shell also exhibits the 
comparatively heavy beak-sculpture, with the radial bars running down the shell 
about 13 to 15 mm. Traces of these are also seen in my larger specimens. 


MEASUREMENTS. 


Length. Height. Diameter. Beaks. 


Santas belcmery.r.0.- 0 crests) ete | 50 mm. |36.5 mm. =73 pr. ct. of L.| 18 mm. =36 pr. ct. of L. |at 18 mm.=26 pr. ct. of L. 
abPlata Myre iey seat noe jes TS By Ro ee Z 32 ee= 38 “ 21 =25 a 

Ost Fersterctac ani ctanars sin eee 87 “ {63 < =72 oe 34 “ =39 os 22 “* =25 - 
lacteolus (Lea’s figure)........)80 “* |51 ase 2 ol =39 ns 23 =29 i: 

Do. (Acc. to Simpson)..... }80 “ {50 a — sy o 30 =38 se 

Do. IDO, ee eS A }72 “ [42 SS Pdi HE Eats) 5 

Do. DOr PPh. nee (ee °** 156 aoe) ia St 
delodontus (D’Orbigny)........)85 “* 70 35 
wymant (Lea's figure). ........ 175 ‘ |49 =65 28 Ss : ee 


The first measurements given by Simpson apparently refer to the type of 
lacteolus, although they do not fully agree with Lea’s figure. The second measure- 


520 MEMOIRS OF THE CARNEGIE MUSEUM. 


ments given by him belong to a specimen which is exceptionally low. The measure- 
ments given by Simpson for wymani do not belong to this species, but to apprimus 
(See above, p. 513, footnote 18). 

I have a suspicion that D. felipponei Marshall (1917, p. 381, PI. 50, figs. 1-3, 
Pl. 51, fig. 1) from Maldonado and other places in Uruguay, is also this species. 
The height as given is 70 to 72 pr. et. of the length, and the general shape and 
other particulars agree, as for instance the hinge-teeth. But, according to the 
figure, felipponei is less pointed behind, and the diameter is a little greater (40 to 
46 pr. et. The color also (yellowish-chestnut) is not exactly like lacteolus, which 
has chestnut-olive-green tints. Thus I leave this question undecided. 


20. DiIPLODON MOGYMIRIM Ortmann, sp. nov. 


Shells: Pl. XX XVII, figs. 4, 5, 6, 7; Anatomy of gills: Pl. XLVI, fig. 5; Section of 
gills: Pl. XLVIII, fig. 2; Glochidium: Text-fig. 4k, p. 469. 


Type-locality.— Creek near Mogy Mirim, Sao Paulo, Brazil, tributary to Rio 
Mogy Guassti and Rio Grande, upper Parans-drainage. J. D. Haseman coll., 
August 28,1908. Type-set: Carn. Mus. Cat. No. 61.9260, fourteen specimens, males, 
barren and gravid females, all with soft parts. (The original lot contained over 
one hundred specimens. ) 

Of all the species of Diplodon known from the upper Parand-drainage in Sao 
Paulo only one described by Von Ihering resembles this in shape: Unio greeffeanus 
(Von Ihering, 1893, p. 96, Pl. 4, fig. 8). However, the color of the epidermis of 
the latter is described as being dark green to blackish, and this does not at all 
fit our specimens, which are brownish black, without any distinct greenish tints. 
Moreover, the dimensions given for the two specimens deseribed by Von Thering; 
although fallmg within the range of variation of my specimens, are rather extreme, 
and do not represent the normal condition of our species. The height is 61 and 
64 pr. ct. of the length, while in my material this proportion varies from 62 to 74 
pr. ct.; and the diameter is 34 and 33 pr. ct., while it ranges, in my specimens, from 
32 to 42 pr. ct. U-. greeffeanus comes from the Piracicaba River (Campinas and 
Piracicaba), while our specimens belong to the Rio Grande drainage. 

From the latter, and especially from Rio Mogy Guassu, at Jaboticabal (not 
“Taboticabal” as printed), Simpson (1914, p. 1250) has deseribed Diplodon trivialis. 
Dimensions and description agree with our specimens to a degree; but again the 
color is different, being described as black or dark brown, and tinted green. when 
rubbed, while in our specimens, when rubbed (cleaned), the epidermis is of a peculiar 


ORTMANN: SOUTH AMERICAN NAIADES. 520 


golden brown, without green. Also the epidermis is not at all “cloth like,” as 
described in trivialis (when fresh), and the description of the pseudocardinals of 
the left valve does not agree at all. There are said to be two pseudocardinals, 
the anterior one sometimes feeble, while in our specimens there is generally only 
one well-developed, and this is the anterior, and if there is a smaller second pseudo- 
cardinal, this is the posterior. The figures of trivialis given by Marshall (1917, 
p. 386, Pl. 54, figs. 5-8) show also that the outline is different, being evenly rounded 
behind. Among my numerous specimens there is not a single one which shows this 
character, and thus I cannot identify them with D. trivialis. 

Description of Shell.—Of moderate size (maXimum length 68 mm.), rather 
solid. Outline short subelliptical or subovate, or subrhomboidal, when young. 
Height from 62 to 74 pr. et. of length. Upper margin nearly straight when young, 
more or less curved when old, in the first case forming an angle with the obliquely 
and rather steeply descending posterior margin, in the latter case passing into it 
more or less gradually. Posterior margin gently concave, straight, or gently 
convex, forming a rounded angle with the lower margin, which may be more dis- 
tinct in older shells. This posterior point is more or less elevated above the base- 
line. Lower margin gently and regularly curved, in older shells more nearly 
straight in the middle. Anterior end of shell slightly narrower than the posterior 
in young shells; in old shells this may be reversed. Thus the shell is, when young, 
more subrhomboidal, with an upper posterior angle (somewhat subalate), and, 
when old, the shell becomes subelliptical or subovate, with the posterior end a 
little tapering. 

Valves rather regularly and evenly convex, sides not distinctly flattened. 
Greatest diameter a little anterior to the middle. Posterior ridge present, but 
rounded and indistinct, often (chiefly in young specimens) marked by a shallow 
radial groove running down the posterior slope, which thus appears as compressed 
and slightly elevated toward the upper-posterior margin (subalate). Diameter 
32 to 42 pr. ct. of the length, so that the shell is rather compressed. Beaks not 
inflated and not much elevated, located at from 25 to 31 pr. ct. of the length. Beak- 
sculpture consisting of fine and short radial bars, hardly more than 5 mm. long, 
fifteen to eighteen in number, those in the middle converging at their lower ends 
(one or two pairs). They are hardly longer upon the posterior ridge, and not ap- 
preciably thicker. A few oblique wrinkles may be present upon the posterior 
slope. In most cases the beak-sculpture is entirely obliterated by erosion of the 
beaks, and in general it is fine, short, and poorly developed. Lunula present, 
narrow in young specimens, wider in old ones, but very variable. 


522 MEMOIRS OF THE CARNEGIE MUSEUM. 


Epidermis somewhat shining, with unequal, irregular, concentric wrinkles, 
more crowded and sublamellar upon the posterior slope and near the margins, 
chiefly in older shells. Radial sculpture may be present, but indistinet, visible 


DO es 


chiefly upon the anterior part of the shell as ‘‘scalariform”’ stripes. Color of epi- 
dermis from yellowish brown to dark brown and blackish, but without any dis- 
tinct traces of greenish tints. In young specimens, when well cleaned, the color 
is generally yellowish or golden brown in the middle of the disk, shading to chestnut- 
brown toward the ends and margins. Older shells are more uniformly chestnut- 
brown to blackish brown (often coated with a dull black-brown deposit). Slight 
traces of darker brown concentric bands are rarely present. 

Hinge-line generally distinctly curved. Ligamental sinus over the posterior 
half or third of the laterals, generally very indistinct in old specimens. Lateral 
teeth curved (less so in young shells), moderately long, one in right, two in left 
valve, their edges and sides corrugated in old shells. Pseudocardinals directed 
obliquely downward and forward, compressed and lamellar, thin in young shells, 
thicker in old ones. The right valve has nearly always two of them, equally high, 
but the anterior narrower. The left valve has mostly only one; but there may be 
a small and short posterior one, and even a small and narrow anterior one. In 
one specimen (one out of over one hundred), the pseudocardinals are exactly re- 
versed: one in right, two in left valve, while the laterals are normal. The edges 
of the pseudocardinals are rugose and crenulated, but not dissected. 

Cavity of shell and beaks moderate. Nacre whitish, but very generally parti- 
ally discolored, with irregular yellowish, brownish, or grayish spots. Anterior 
adductor-scar impressed, rounded or subtriangular; anterior retractor-scar separated 
from it, rounded or irregularly oval, impressed, but not remarkably deep; anterior 
protractor-scar connected with adductor-sear. Posterior adductor-scar ovate or 
subtriangular, less deeply impressed; posterior retractor-sear generally separated 
from it, but sometimes only indistinctly so. Pallial line distinct. Dorsal sears 
few and irregular, in beak-cavity, forming an indistinct longitudinal row. 


MEASUREMENTS. 


No Sex.| Length. | Height. | Diameter. Beaks. Figured. 
49. | 31 mm.|22) mm.=71 pr. ct. of L.}11 mm.=35 pr. ct. of L.'at 8.5 mm. =27 pr. ct. of L.| 

12 oO | 39 Ve eda (ars) My IPA ee ay > 11 $ 8 2 Pl. XXXVII, fig. 6. 
18:..| 9 | 40:5 “* |30 yi! i 15 SS 3y, a 11 ; 27 ee 

9. o' | 53 “136 “« =68 a 20 “« =88 Wr = IB Gy 4 as Ho Pl. XX XVII, fig. 5. 
ATs HONG See se 39, ee =e ae 26) eal : No aie O27 me 

Sun sf 2) | 64.5. & 140 a O2) oe 27 AZ, 7 17 20) ry 
34... 9 | 68 “143 = 183) * PASS SF 8453 21 ol x 

1625S) 1968 Salad OD i. 26 oo s}s! “8 18 20 & 


ORTMANN: SOUTH AMERICAN NAIADES. 523 


Remarks.—This species somewhat resembles D. lacteolus, but is considerably 
smaller, has finer and shorter beak-sculpture, and, when old, has more simple, 
less dissected pseudocardinals, of which those of the right valve are more nearly 
equal. The young shell (Pl. XX XVII, fig. 6a) has rather a subrhomboidal shape, 
exactly as D. lacteolus, which is due to the better development of the angle between 
the upper and posterior margins, which appears as slightly elevated (alate). ‘Thus 
the young shell is slightly higher in its posterior section, with the posterior end of 
the shell less elevated above the base-line, giving to the whole shell a slightly oblique 
appearance. But this juvenile shape is sooner or later obliterated, the posterior 
wing disappearing, and the posterior end becoming more tapering, giving to the 
shell a rather subovate outline, with the posterior end subpointed; but this point 
is never very distinct. The outline of Von Thering’s greeffeanus (PI. 4, fig. 8) comes 
very near to the normal shape of the old shell of D. mogymirim. The brownish 
color of the epidermis of our species is also characteristic, and the complete absence 
of distinctly greenish tints is to be noted. 

Anatomy.—I have a great number of the soft parts of males and of barren and 
eravid females, the latter partly with eggs, partly with glochidia in various stages 
of development. Of fifty specimens the anatomy has been investigated more 
closely. For the breeding season the date of collection (August 28) should be 
noted. 

Color of soft parts brownish white. 

Anal opening slit-like, closed above; closed part not quite twice as long as 
the open part. Anal about as long as the branchial, separated from it by a solid 
mantle-connection. Branchial opening with distinct papille. Palpi moderate, 
subtriangular, posterior margins connected for about one-third of their length. 

Gills (Pl. XLVI, fig. 5a, b, c) rather wide, the outer one subtriangular, pos- 
teriorly slightly wider than the inner; the inner one subtrapezoidal, anteriorly 
wider than the outer, its anterior end immediately behind the palpi. Inner lamina 
of inner gill entirely connected with abdominal sac. Non-marsupial gills (PI. 
XLVI, fig. 5a) with few, seattered interlaminar connections. The marsupium 
(Pl. XLVI, fig. 5b) of the females located in the inner gills, but occupying only 
a part, anteriorly leaving free not quite one-third of the gill, and posteriorly hardly 
one-fourth, so that the marsupium gravitates slightly toward the posterior section 
of the gill. In young females, the marsupial part (Pl. XLVI, fig. 5)) is much 
smaller, and lies distinctly behind the middle of the gill. Structure of the mar- 
supium (Pl. XLVI, fig. 5¢ and Pl. XLVIII, fig. 2a, 6) quite peculiar, consisting of 
uninterrupted septa, forming well isolated water-tubes. An interrupted or reticu- 


524 MEMOIRS OF THE CARNEGIE MUSEUM. 


lated arrangement of the interlaminar connections is nowhere to be seen. Never- 
theless this structure must be regarded as developed out of the interrupted con- 
dition of the septa, since the non-marsupial gills distinctly show the latter (PI. 
XLVI, fig. 5c). In consequence of the development of the water-tubes, the egg- 
masses fill these tubes (the ovisaes) in placenta-like bodies (conglutinated); how- 
ever, these are not very solid and persistent. 

Glochidium (text-figure 44, p. 469) subtriangular, longer than high, rather 
small. L. 0.29, H. 0.283 mm. They are slightly oblique, with the lower point 
vertically under the posterior third of the hinge-line. They have hooks of the 
usual shape, about 0.09 mm. long. Immature glochidia have no hooks. 


21. DipLopon suavipicus (Lea) (1856). 
Unio suavidicus Lea, Obs., VI, 1857, Pl. 29, f. 24. 
Diplodon suavidicus Simpson, 1900, p. 876; 1914, p. 1240. 

Type-locality.— River Amazon. 

New Locality—Rio Tapajos, Santarem, Parad, Brazil (J. D. Haseman coll., 
December 6-12. 1909). Six specimens and three isolated right valves. 

Description.—Shell small, greatest L. 28 mm., moderately solid, angularly 
subovate or subtrapezoidal, but little oblique, slightly narrower in front, somewhat 
broader and sub-pointed behind. Height 69 to 76 pr. et. of length. Valves not 
gaping; dorsal margin gently curved, descending posteriorly, anteriorly descending 
more steeply, and passing insensibly into the anterior margin, posteriorly passing in 
a rather distinct (indistinct only in largest specimens) but blunt angle into the 
posterior margin, which descends obliquely, and is straight or very gently curved. 
Lower margin ascending gently in its posterior part, and meeting the posterior 
margin in a more or less distinet, but rounded, angle, forming the posterior point 
of the shell, which is a little elevated above the base-line. Anterior part of lower 
margin longer, sloping distinetly upward. It may be almost straight, or very 
gently curved, curving up into the anterior margin. Thus the anterior part of 
the shell appears somewhat narrower than the posterior. 

Valves moderately convex, slightly flatter on the sides. Umbonal ridge 
rather distinct, but rounded. Posterior slope compressed, produced in young 
specimens into a slight wing-like elevation of the posterior angle of the upper 
margin. In some specimens there is a bare indication of a radial rib upon the pos- 
terior slope. Diameter 48 to 50 pr. et. of length. Beaks not much swollen, little 
elevated above hinge-line, located at 22 to 29 pr. ct. of length. Beak-sculpture 
rather well developed, extending upon the umbonal ridge about 10 mm. or more, 


ORTMANN: SOUTH AMERICAN NATADES. 525 


but not quite so far upon the rest of the shell, and covering altogether about one- 
third or one-fourth of the shell. There are about fifteen or sixteen radial bars, of 
which the eighth and ninth unite, and between the latter there is another shorter 
pair, also united in v-shape. These bars are rather sharp, those just in front of the 
umbonal ridge are hardly broader. The most anterior bars are sometimes slightly 
granular, occasioned by the growth-lines cutting across them. There are generally 
close to the beaks a few additional radial bars upon the posterior slope, and below 
then some oblique, irregular wrinkles, sometimes crossing the former, so as to 
form v-shaped angles (forming the posterior system of re-entering angles of Lea). 
Lunula present, short, narrower or wider. 

Epidermis with numerous, fine, concentric growth-lines, sublamellar on pos- 
terior slope, and in the larger specimens with traces of radial lines, chiefly in the 
front part of the shell. Color brown to blackish brown, without color-markings. 

Hinge-line gently curved. Ligamental sinus over the posterior third of the 
laterals. Lateral teeth gently curved, thin, one in right, two in left valve. Pseudo- 
cardinals obliquely descending, rather long, compressed and thin, two in right 
valve, the posterior more elevated, with serrated edge. In the left valve also 
two pseudocardinals, the anterior larger, serrated, the posterior much smaller, 
sometimes rudimentary. 

Cavity of shell and beaks moderate. Nacre whitish. Anterior adductor- 
sear moderately impressed. Anterior retractor-scar separated, and anterior pro- 
tractor-scar united with adductor-sear. Posterior scars indistinct, united. Dorsal 
sears in beak-cavity. 


MEASUREMENTS. 


No. Length. | Height. | Diameter. | Beaks. 
: | = 3 E : 9° . 
Det artes 18 mm. |/13 mm.=72 pr. ct. of Th 9 mm.=50 pr. ct. of L.at 4 mm. =22 pr. ct. of L. 
72] I 4 2] 
ZS Oe er US: 14 “ =76 oe | 9 “  =49 Ss 5 “ =27 a 
4 21 SS  =71 e | 9 a . Ca — 29 § 
i ee ae ST) Ba IG NOS ATS GR ee a as 298 ak 
Ott a 27 118.5 ‘© ='69 HY 2 “  =44 ff C29 eS 
Cae er IRB A Olen Sos = ef [12 = 43 P: 8) = 29 : 
Lea’s figure. | 21 e 15 perl a oe eto ss Ce! : 


Remarks. My specimens are rather uniform in shape and proportions. There 
is some variation in the posterior part of the ventral margin, which may ascend a 
little more decidedly, giving to this margin a more distinct lower projection, and 
placing the posterior point of the shell a little higher above the base-line. In 
my largest specimen, all angles (upper posterior, posterior, and that of lower 
margin) are more rounded. The beak-seulpture may be more or less distinet and 
sharp, and the bars vary somewhat in length. 


526 MEMOIRS OF THE CARNEGIE MUSEUM. 


Previously this species was known only from a single individual described 
by Lea. There is not the slightest doubt that my specimens belong here, and one 
of them (No. 4) is almost a replica of that of Lea. Lea believes that his shell is 
a young one, and it certainly is not full-grown, but, as my material shows, this 
species does not grow very much larger. Von Ihering (1898, p. 120) suggests 
that this might be the young stage of U. wheatleyanus Lea, but this cannot be the 
case, since the latter has a different, much heavier beak-sculpture. 

I am uncertain about the systematie position of this species, but there are 
certain resemblances in the shape of the shell to that of the lacteolus-group. This 
species is also interesting because of the fact that it is one of the few forms of 
Diplodon found in the Amazon-drainage. 


6. Group oF Diplodon ellipticus. 

Shell more or less elongated, but often rather high and short; subovate or 
subtrapezoidal, distinctly oblique at all stages of growth, with the longest axis 
forming an angle with the line of the ligament. Anterior end narrower, posterior 
end higher, and lower margin distinetly ascending in its anterior portion. Beak- 
sculpture fine or coarse, more or less developed. 

The chief character of this group is the obliquity of the shell, brought about 
by a widening of the posterior portion of the shell in the vertical direction, so that 
the posterior end lies rather low, and the longest dimension is not parallel or nearly 
parallel to the ligament, but forms a distinct angle with it. Although an obliquity 
is sometimes indicated in the species of the previous groups, it generally disappears 
with increasing age, while in the present group the obliquity is rather emphasized 
in older shells. It is all-important, in order to correctly Judge as to the shape of 
these shells, to place them in a uniform position, always with the ligament running 
horizontally. 

The outline of the shells of this group varies a good deal, and some of them 
become very high in proportion to length, so that the outline appears more nearly 
subrotund, similar to the shape in the subgenus Cyclomya. However, in the 
latter the greatest height of the shell is always situated more nearly in the middle 
under the middle of the ligament, while in the shells of the ellipticus-group the 
greatest height is more posteriorly, at the posterior end of the ligament, or even 
beyond that. 

22. DIPLODON ELLIPTICUS Spix (1827). 
Diplodon ellypticum (error typogr.) Sprx, 1827, Pl. 26, fig. 1-2. 
Unio ellipticus WAGNER, 1827, p. 33; Von InERING, 1890, p. 163, Pl. 9, figs. 8-9; 

Von Ihering, 1893, p. 108. 


ORTMANN: SOUTH AMERICAN NATADES. 527 


Diplodon wagnerianum Simpson, 1900, p. 877; 1914, p. 1246. 

Type-locality. Rio San Francisco (Wagner). 

Other Localities —Rio Parahyba do Sul, Rio de Janeiro (Von Thering, 1893, p. 
115); Rio Santa Maria, Espirito Santo (Von Thering, 1910, p. 134) (drainage of 
Rio Doce). The form from the latter locality has been named var. santanus Yon 
Ihering. 

Rio Piracicaba, Sio Paulo, and Rio Tamanduatahy, Sao Paulo (Von Thering). 
The latter two localities are somewhat doubtful, since the specimens are not exactly 
like ellipticus. The location and drainage of the last named river is unknown to 
me. 

In the Carnegie Museum is one specimen, labeled ‘“ Brazil’? (Holland Collec- 
tion). Not quite typical. 

The change of the specific name ellipticus to wagnerianus is unwarranted. 
Spix gave the name in the plate in connection with the generic name Diplodon. 
Since the latter stands, the specific name also is entitled to recognition. 

In spite of Von Ihering’s re-description of the type, this species is as yet poorly 
known, and our knowledge of it is founded chiefly upon what Von Thering has 
said. The species is positively known from the Rio San Francisco and the Rio 
Parahyba do Sul; the other localities are more or less doubtful, since the specimens 
deseribed from them do not fully agree with the type. Those from the Rio Santa 
Maria have been distinguished as a variety. 

All we can gather from descriptions and figures is that D. ellipticus is a sub- 
elliptical or subtrapezoidal shell, of dark green to blackish color, with rather smooth 
surface. It has in the anterior part of the shell a shallow depression, often producing 
a shallow emargination in the anterior part of the ventral margin. In outline, 
the shell is distinctly oblique, narrower in front, higher behind. The beak-sculpture 
consists of simple, fine radial bars, which are rather short, and somewhat cut up 
on the posterior slope by irregular, oblique wrinkles. The nacre is blueish white. 
Pseudocardinals somewhat compressed, but not thin, crenulated, two in right, 
one in left valve, but the latter with an angle at its base, representing the remnant 
of a posterior tooth. 

Our specimen from Brazil was received as ellipticus. It agrees in most of the 
above characters, except that it is shorter in proportion to height, with less pointed 
posterior end. Also the projection of the lower margin is indistinct. The beak 
has eleven radial bars in front of the posterior ridge, the seventh and eighth meeting 
in the middle. On the posterior slope there are corrugations and fine, oblique 
ridges. L. 32 mm.; H. 21 mm.; D. 12 mm. This specimen might very well be 


528 MEMOIRS OF THE CARNEGIE MUSEUM. 


a young elliplicus, and may correspond to the var. santanus of Von Thering (smaller, 


projection of lower margin less distinct). 


23. DIPLODON BERTH Ortmann, sp. nov. 
Shells: Plate XX XVIII, figs. 1, 2, 3, 4; Anatomy of gills: Plate XLVI, fig. 6. 

Type-locality.—Rio Jacuhy, Cachoeira, Rio Grande do Sul, Brazil (J. D. Hase- 
man coll., January 26, 1909). Type-set: Carn. Mus. Cat. No. 61.5865. Sixteen 
specimens, all with soft parts, including males, barren and gravid females. (There 
were twenty-three specimens in the original lot). 

Additional Locality—Rio Vaceahy Mirim, Santa Maria, Rio Grande do Sul, 
Brazil (J. D. Haseman ecoll., January 29. 1909). One male with soft parts. 

Distribution: Guahyba drainage in southern Brazil. 

Description of Shell—Shell rather small, maximum length 65 mm.; rather 
solid, chiefly so anteriorly, and in old shells often much thickened along the lower 
anterior margin. Outline subovate to subtrapezoidal, distinetly oblique, broad 
and rounded, or somewhat pointed behind. Height from 55 to 67 pr. et. of length. 
Valves not gaping. Dorsal margin straight, or gently descending posteriorly, 
forming a more or less distinct obtuse angle with the posterior margin. The latter 
obliquely descending, gently convex, and curving around into the posterior part 
of the lower margin, forming with the latter in young specimens an indistinct 
rounded angle, which, however, may become more distinct in old specimens. Lower 
margin in normal specimens with a distinct rounded projection, forming the lowest 
point of this margin, situated far back, behind the posterior end of the ligament. 
From this point the lower margin curves up behind to the posterior end of the shell 
and this part is quite short. Anteriorly the lower margin also slopes upward, 
and is almost straight for a considerable distance; sometimes it is even slightly 
concave; then it curves up into the anterior margin. Thus the shell appears con- 
siderably narrower anteriorly, broader (higher) posteriorly, with the greatest 
height situated far backward. 

Valves moderately and not uniformly convex. The greatest convexity is near 
the anterior end and over the posterior ridge, which is broad and not sharply marked. 
In front of the posterior ridge the sides of the disk are distinctly and broadly flat- 
tened, and sometimes even slightly concave, producing the emargination of the 
anterior part of the lower margin. Posterior slope somewhat compressed, very 
rarely with a slight trace of a rib or a furrow. Greatest diameter of the shell 32 
to 43 pr. et. of the length, located well behind, upon, or close in front of, the pos- 
terior ridge. Thus, although rather swollen in the region of the posterior ridge, 


ORTMANN: SOUTH AMERICAN NAIADES. 529 


the shell appears in front of it rather more compressed. Beaks not much swollen, 
and not very prominent, located at from 23 to 29 pr. ct. of the length. Beak- 
sculpture consists of twelve to fourteen radial bars, which are sharp and rather 
distant from each other, the ninth, tenth, and eleventh (immediately in front of 
and upon the posterior ridge) are longest, about 10 to 12 mm. long; the seventh 
and eighth may consist of two bars united in V-shape, but this cannot be seen 
clearly, since in all specimens the tips of the beaks are eroded. These median 
bars (seventh and eighth) are also slightly shorter than those in front, and distinctly 
shorter than those behind them; the last two or three bars are fine and somewhat 
shorter, and stand upon the posterior slope, becoming indistinct. In a few of my 
specimens there are traces of oblique wrinkles upon the posterior slope. Lunula 
short and narrow, distinct only in larger specimens. 

Epidermis smooth, rather shining, with numerous, closely set, fine, concentric 
lines, and stronger and irregular concentric wrinkles. The fine lines become sub- 
lamellar on the posterior slope and towards the margins. A fine radial sculpture 
is present, chiefly in the anterior part of the shell, but it is not very evident. Color 
greenish black to brownish black, darkest in old shells. Young shells are more 
distinctly greenish, dark olive-green, shading towards the beaks to gray-green and 
brownish olive. There are no distinct color-bands and no distinct color-rays, 
except in very young specimens, where there are traces of dark green rays on the 
posterior slope, seen when held up against a strong light. 

Hinge straight or gently curved. Ligamental sinus over the posterior third 
or fourth of the laterals (more posteriorly in old shells). Lateral teeth curved, 
more strongly so in their posterior part in old shells, one in right, two in left valve, 
edges rugose. Pseudocardinals two in right, one in left valve, subcompressed, 
not very long, in old specimens sometimes almost stumpy. The posterior pseudo- 
cardinal of right valve stronger and more elevated than the anterior, often much 
divided, and always much crenulated. Very often there is a second posterior 
small pseudocardinal in the left valve. 

Cavity of shell and beaks shallow. Nacre whitish, in old specimens often 
very thick anteriorly, and with pinkish tints; posteriorly very iridescent. Ad- 
ductor-scars deeply impressed anteriorly, less so posteriorly. | Anterior retractor- 
scar small and deep, separated from the adductor-scar; anterior protractor-scar 
united with it. Posterior retractor-sear connected with adductor-sear. Pallial 
line distinct. Dorsal sears in an oblique irregular row in the beak-cavity. 

Remarks.—This species may be what Von Thering (1893, p. 102) calls wthiops 
in the Guahyba drainage, but only the remark (p. 104) that this @wthiops has a 


530 MEMOIRS OF THE CARNEGIE MUSEUM. 


broad, shallow furrow in the anterior part of the shell, seems to confirm this as- 
sumption. In other respects it is impossible to decide, whether this is, or is not, the 
wethiops of Von Ihering. It surely is not the ethiops of Lea. Of the few other 
species incidentally mentioned by Von Ihering as found in the Guahyba-drainage, 
none can be compared with our species. Its chief characters are the subovate to 
subtrapezoidal distinctly oblique shape, narrow in front, broader behind, and the 
peculiar compression of the shell in the anterior part. The beak-sculpture and 
color of the epidermis are also characteristic. 


MEASUREMENTS. 


No ‘Sex| Length Height Diameter. Beaks. | Figured. 


Tague | 
pr. ct. of L.|Pl. XX XVIII, fig. 2. 


3...| o' | 31.5 mm./21 mm. =67 pr. ct. of L.|10 mm. =32 pr. ct. of L.Jat 8 mm. =25 

11. 4825) oo 27 pee O5: ok 1s Schl L2D is oe 29 

14. 9 | 47 oe [olLOMinet—O7, 19 nx oA () IDs Ce —P7/ 

22. 2 | 51.5 “ 132 Sea O92 - 22 S85 ae 12 a 

PETE | Ae EY = (29 OO) fa 210) => =A vs | 12 a2) | 

24. OU] 56: “ 136 SO ae PAS BTS} x 13.5 =24 Pl. XXXVIII, fig. 1. 
34. a! 65 “> (Bozo oe eo = 26 pone) 15 = 33} (Santa Maria) 


I cannot compare this species with any other, except D. ellipticus Spix. The 
general shape is very much the same, but ellipticus seems to be more elongate 
(height only 54 pr. et. of length). The posterior end is slightly more pointed, and 
the diameter is distinctly less (31 pr. ct. on the average). In our species the average 
height is 62 pr. et. and the diameter 39 pr. et. In addition our shell seems to be 
thicker and more solid, chiefly in old specimens, where the lower anterior margin 
is considerably and strikingly thickened, a character not mentioned in ellipticus. 

Old shells often become freakish, assuming irregular shapes. Frequently the 
posterior part of the shell grows more strongly in length, thus rendering the shell 
exceptionally long (as in No. 23). In such specimens the projection of the lower 
margin is obscured, and the posterior point of the shell is very little elevated above 
the base-line. Furthermore the shell in general is more pointed behind. Such 
specimens also appear more swollen. However, the growth-lines clearly indicate 
that, when young, these individuals had the normal shape. In other old shells 
the whole posterior part is more developed (No. 24, Pl. XX XVIII, fig. 1a) and is 
deflected downward. This fact tends to preserve the general shape, but renders the 
anterior part of the lower margin somewhat concave. 

Anatomy.—Judging from the soft parts at hand, twelve specimens are males, 
five are barren females, and seven are gravid females. Only one of the latter con- 
tained immature glochidia. The date of collection (January 26) apparently is 
near the beginning of the breeding season. 


ORTMANN: SOUTH AMERICAN NAIADES. 531 


Color.—Distal part of foot dark brownish, grayish, or blackish; the rest of 
the soft parts are whitish. 

Anal opening closed above; the closed part about four times as long, or a little 
longer than the open part; the latter slit-like, slightly shorter than the branchial 
opening. The latter with small, but distinct papillae, separated from the anal by 
a solid mantle-union. Palpi subtriangular, moderately large, of the usual shape; 
their posterior margins connected at base. 

Gills rather long and wide. Outer gill subtriangular, widest at the beginning 
of the posterior third, and here it projects a little beyond the inner gill. Inner gill 
subtrapezoidal, its anterior end immediately behind the palpi. Inner lamina of 
inner gill connected with abdominal sae. 

Structure of non-marsupial gills as usual. In the female, the marsupium (Pl. 
XLVI, fig. 6) is located in the inner gill, and in large specimens it is restricted to 
the middle part of the gill, leaving non-marsupial almost one-third at the anterior 
end, and a somewhat smaller portion at the posterior end. In young specimens 
the marsupium is smaller. When charged, the marsupium forms a slightly swollen, 
lenticular, rounded, or oblong patch in the middle of the gill, most of it lying behind 
the middle. The interlaminar connections of the marsupium are strongly de- 
veloped, forming very incomplete, interrupted septa, and arranging themselves 
rather in transverse and oblique rows, so that the vertical septiform structure is 
obscure, while a reticulate and irregularly quincuncial arrangement prevails. 
Only near the margin of the gill is a septiform structure indistinetly indicated. 
The egg-masses do not conglutinate into placente-like structures. 

Only one of my females has very young glochidia. They are, as far as can be 
seen, of the usual shape, subtriangular, and somewhat oblique. Exact measure- 
ments could not be obtained. No hooks are visible, but, of course, such may be 
present in ripe glochidia. 


24. DIPLODON ENNO Ortmann, sp. nov. 
Shells: Plate XX XVIII, figs. 5, 6, 7, 8; Anatomy of gills: Plate XLVI, fig. 7. 


Type-locality.— Rio Grande, Boqueirao, Bahia, Brazil (S. Francisco drainage). 
(J. D. Haseman coll., January 9, 1908). Type-set: Carn. Mus. Cat. No. 31.9264. 
Eighteen specimens, males and barren females, with soft parts. (A number 
of additional young specimens were in the original set.) 

According to the latest census of the Naiades from the Rio S. Francisco 
drainage (Von Ihering, 1910, p. 138), there are only two species of Diplodon present 
in this system: D. rotundus Spix, and D. ellipticus Spix. The former is much 


532 MEMOIRS OF THE CARNEGIE MUSEUM. 


higher and much more rounded than the present species; the latter is more elongated 
and more pointed behind, and has, besides, a smooth epidermis (Cf. Von Ihering, 
1890, p. 163). Since it is impossible for me to find any other South American 
species of Diplodon, the description of which answers to the present species, we 
must regard the latter as new. 

Description of Shell.—Shell small to medium (maximum length 53 mm.), 
rather thin. Outline subovate or subtrapezoidal, distinetly oblique, higher behind, 
narrowed anteriorly, the obliquity being most pronounced in older specimens. 
Height 56 to 75 pr. et. of length (against 54 pr. et. in ellipticus, and 86 or 87 pr. ct. 
in rotundus). Valves not gaping. Dorsal margin straight or gently convex, form- 
ing a rather distinct or obtuse angle with the posterior margin, which descends ob- 
liquely and rather steeply, is nearly straight or gently convex, and curves into 
the lower margin without forming a distinct posterior point. The posterior ex- 
tremity of the shell is located relatively low and is only moderately elevated above 
the base-line. Lower margin with its lowest point located rather posteriorly, 
vertically below the posterior end of the ligament, or even behind it, strongly as- 
cending in a curve toward the posterior end of the shell, but nearly straight or 
very slightly convex in its anterior part, and sloping upward toward the anterior 
margin, so that the anterior portion of the shell is distinetly narrower than the 
posterior, producing thus the oblique appearance of the whole shell. 

Valves comparatively compressed. Diameter 28 to 45 pr. ect. of length. 
Greatest convexity and greatest diameter situated well back upon the posterior 
ridge, which, however, is very indistinct and broad. Sides of the shell in front of 
posterior ridge not very convex and rather flattened. Posterior slope compressed, 
sometimes with a faint trace of a radial groove, somewhat elevated (wing-like) 
toward the upper posterior angle. Beaks not swollen, and hardly elevated above 
the hinge-line, located at from 22 to 28 pr. et. of the length. Beak-sculpture 
sharp and fine, distinct, but restricted to the region near the beaks. There are 
fifteen to eighteen radial bars, the ninth and tenth in the middle, joined and v- 
shaped at their lower ends. . The longest bars (6 to 8 mm.) stand upon the posterior 
ridge, the anterior ones being distinctly shorter. There are a few anterior bars 
and upon the posterior slope a few posterior bars, and sometimes traces of oblique 
wrinkles. None of the bars are distinctly granular, and a comparatively slight 
degree of erosion obliterates all traces of beak-sculpture. Lunula indistinet and 
narrow, visible only in older shells. 

Epidermis not shining, but rather rough. This is due to a great number of 
fine, irregular, concentric lines, which, when well-preserved, are lamellar and 


ORTMANN: SOUTH AMERICAN NAIADES. 533 


elevated, showing this character all over the disk, being, however, more distinctly 
lamellar and more crowded upon the posterior slope and near the margins. Even 
when these fine lamellx are worn off, the epidermis does not become shining, but 
remains dull, and when well-preserved, the epidermis appears cloth-like. There 
are no traces of radial sculpture. Color of epidermis dark greenish black, but 
often in the middle of the disk and towards the beaks brownish black. The greenish 
tint is not very evident, and is best seen in young specimens. 

Hinge-line very gently curved. Ligamental sinus over the posterior third of 
the laterals. Lateral teeth curved, one in right, two in left valve, their edges 
slightly corrugated or nearly smooth. Pseudocardinals narrow and compressed, 
but not very long, corrugated and rugose, but not cut up, two well developed 
pseudocardinals of nearly equal size in right valve, one well-developed in left valve; 
but there often is a smaller posterior one in the left valve, and another small, low, 
‘and narrow anterior one, so that the left valve may have three pseudocardinals. 
The middle one, however, is always the largest. Sometimes the posterior pseudo- 
cardinal of the right valve is higher and thicker than the anterior. 

Cavity of shell and beaks shallow. Nacre blueish silvery, very iridescent, 
and sometimes discolored yellowish. Anterior adductor-scar distinct and moder- 
ately impressed. Anterior retractor-scar rounded, small and rather deep, separ- 
ated from adductor-sear. Anterior protractor-scar united with it. Posterior 
adductor-scar rather indistinct and not impressed, the posterior retractor-scar 
forming an upper process of it. Pallial line not very sharp. Dorsal sears few in 
beak-eavity. 


MEASUREMENTS. 

No. |Sex. Length. | Height. | Diameter. Beaks. Figured. 
ikea) Legal el PEGS mm.| 7 mm. =56 pr. ct. of L. 3.5 mm. =28 pr. ct. of L.'at 3.5 mm. =28 pr. et. of L. 
140% 2)? |-22 Beal Wis Baye Tes Prey oe 7 se 2 | 6 Sey se 

8...| o' | 28 Be TAO EES 83 7 9 =32 7 = 25 

4...) | 35 ** 126 e118 12 =34 8 =23) Pl. XXXVIII, fig. 5. 
2a | 45 pz = dd 16.5 =or ee) =I PI. XX XVIII, fig. 8. 
tise] UH GB “140 Sh 24 — 5 TES =24 Pl. XX XVIII, fig. 7. 


Remarks.—The dimensions of this species change slightly with age, in that 
younger shells are not so high in proportion, and consequently, they appear 
less distinctly oblique than older ones. The diameter of young shells is also less 
than in old ones, and the highest figures (37 to 45 pr. et.) are shown by old females. 
In other respects my specimens are rather uniform, and the oblique, not very 
elongated shape, and the dull, blackish epidermis and silvery nacre are chiefly 
characteristic. 


534 MEMOIRS OF THE CARNEGIE MUSEUM. 


Anatomy.—It was not possible to positively ascertain the sex of my smallest 
specimens. But, I have other specimens, of which five are positively males, and 
seven of which are females. None of the latter were gravid. 

Color of soft parts whitish, distal part of foot brown. 

Anal opening closed above; closed part considerably longer than the open 
part; the latter slit-like, shorter than the branchial opening, and separated from 
it by a solid mantle-connection. Branchial opening with distinet papille.  Palpi 
subtriangular, their posterior margins connected for about one-third of their 
length. 

Gills of the usual shape, rather wide, the inner anteriorly wider, its anterior 
end close to the palpi. Inner lamina of inner gill entirely connected with abdominal 
sac. Non-marsupial gills of the usual structure, with few and scattered inter- 
laminar connections. Marsupium of the female (Pl. XLVI, fig. 7b) located in 
the mner gill, occupying nearly half of it in the middle, leaving non-marsupial 
one-fourth of the gill both at the anterior and posterior end. In young females 
the marsupial part is smaller (Pl. XLVI, fig. 7a), but also located nearly centrally. 
Interlaminar connections of the marsupium reticulated or quineuncial toward the 
base, but forming interrupted septa toward the margin. 


25. DipLopon Gratus (Lea) (1860). 

Section of gills: Plate XLVIII, fig. 3. 
Unio gratus Lma, Obs., X, 18638, Pl. 43, fig. 290; SowerBy, XVI, 1868, PI. 84, fig. 444. 
Diplodon (Cyclomya) gratus Stupson, 1900, p. 886. 
Diplodon (Cyclomya) fontainianus gratus Simpson, 1914, p. 1281. 

Type-locality—Rio Uruguay. 

New Locality—Rio Uruguay (in mud), Uruguayana, Rio Grande do Sul, 
Brazil (J. D. Haseman coll., February 5, 1909) twenty-one specimens, males 
and females, all with soft parts. 

Distribution.— Positively known only from the Uruguay River. Von Ihering 
(1893, p. 92) gives this form also from Rio Guahyba, Porto Alegre, Rio Grande 
do Sul. However, as we shall see, this is not the typical gratus, and the Guahyba- 
form has already been distinguished by Simpson as var. deceptus (see below). 

Description of Shell—Rather small, maximum length of my specimens 53 mm., 
moderately thick. Outline obliquely subrotund, subovate, or subtrapezoidal, 
very variable, more or less high (height 72 to 85 pr. ect. of length). There is an 
indistinct relation of the shape to sex, in so far that the highest shells (79 pr. et. 


_and over in height) are all males, while the more elongated specimens may be either 


ORTMANN: SOUTH AMERICAN NAIADES. i, 


males or females, the former being more subrotund, the latter more subovate- 
subtrapezoidal. Dorsal margin gently convex, forming a more or less distinct, 
obtuse angle with the posterior margin, the latter obliquely descending, straight, 
or gently curved, curving broadly around into the lower margin, forming the in- 
distinctly defined, rounded, posterior end of the shell. Lower margin ascending in 
its anterior part, gently curved in the higher shells, or almost straight in those 
more elongated, its posterior part curving up towards the posterior margin. The 
lowest point of the lower margin (and greatest height of shell) is located well back- 
ward, vertically below the posterior end of the ligament, or even behind this. Thus 
the shell presents a rather oblique shape, being narrowed anteriorly, and higher 
posteriorly, but, according to the varying height, this obliquity is more or less 
pronounced, most distinctly in the more elongated shells, less so in those more 
elevated, where the outline approaches the subrotund shape. 

Valves moderately but variably convex, convexity greatest upon the broad 
posterior ridge, smallest upon the sides of the disk, where elongated specimens 
are almost flat. Posterior slope slightly compressed, sometimes with a trace of a 
radial furrow and a ridge, which, however, may be entirely obliterated. Diameter 
36 to 50 pr. et. of length. The more compressed specimens are the smaller, but 
no distinct relation to sex can be discovered in this. Beaks moderately swollen, 
not very prominent, located at 25 to 34 pr. ct. of the length (more anteriorly in 
larger specimens). Beak-sculpture weakly developed, seen only in smaller speci- 
mens, consisting of twelve to thirteen radial bars, of which the seventh and eighth 
unite v-shapedly. The bars do not differ much in length, although the posterior 
ones are slightly longer, the maximum being hardly over 8 mm. long. They are 
not very sharp, but rather blunt, only the most anterior and posterior (upon pos- 
terior slope) are somewhat finer and sharper. Often there are upon the posterior 
slope irregular oblique wrinkles, which may be rather numerous, or may be al- 
together absent. Lunula absent in young, but sometimes seen in older specimens, 
short and very narrow. 

Epidermis smooth in the middle of the disk, but not very shining, covered 
with numerous somewhat irregular, fine, concentric lines, and more widely separated 
irregular concentric wrinkles. The concentric lines are sublamellar upon the an- 
terior end, the posterior slope, and towards the margin, and sometimes they are 
sublamellar all over the disk, but the latter is the case only in young individuals. 
In old specimens they undoubtedly have been worn off. Radial sculpture generally 
present. It may be very obscure, chiefly in younger shells, but is visible in older 
shells, consisting of faint, blunt radial ridges, which are rather irregular, often in- 


536 MEMOIRS OF THE CARNEGIE MUSEUM. 


terrupted, and more distinct in the anterior part of the shell. Even when best 
developed, they do not constitute a prominent feature of the surface. Color of 
epidermis dark olive-green to blackish. In young specimens it is more grayish 
or brownish green towards the beaks; in older specimens it appears nearly black. 
When slightly worn, it is in places lighter, brownish olive, or greenish olive. In some 
older specimens brownish tints appear towards the lower margin, and sometimes 
a faint brownish concentric band is indicated. The general impression of the 
color of the epidermis, however, is blackish green, not brown. No color-rays are 
visible. 

Hinge-line gently curved. Ligamental sinus over the posterior third of the 
laterals, in young specimens over the posterior half. Lateral teeth curved more 
strongly in their posterior part in old shells, one in right, two in left valve, their 
edges rough. Pseudocardinals directed obliquely forwards and downwards, 
lamellar and compressed, but not very long. In the right valve there are two of 
them, the posterior much larger than the anterior. In the left valve there is one 
pseudocardinal, but quite often a smaller posterior one is present. All pseudo- 
cardinals are rough, crenulated, or serrated. ; 

Cavity of shell and beaks moderate. Nacre whitish, iridescent, in young 
shells blueish or greenish silvery towards the edges. In older shells it becomes 
more opaque white, and assumes generally a creamy or salmon hue in and near 
the cavity. In a few specimens there is a very delicate pinkish tint all over the 
nacre. ; 

Anterior adductor-scar rather deep, subelliptical; anterior retractor-scar 
small, deep, isolated from the adductor-sear; anterior protractor-sear connected 
with it. Posterior adductor-sear subtriangular, faintly impressed, posterior re- 
tractor-scar forming an upper triangular process of it. Pallial line distinet. | Dorsal 
sears few, in an irregular, oblique line in the beak-cavity. 


MBASUREMENTS. 


No. | Sex. Length. Height. | Diameter. Beaks. 


b...|. 2? |23.5mm./ 7 mm.=72 pr. ct. of L.| 8.5 mm.=86 pr. ct. of L.| at 7.5 mm.=82 pr. ct. of L: 
2. Ver N2StD no: aloo e 35 i 11 « =39 : 9 «" =32 oe 
3. 2 132 : \2d.00 — = 73 ts 14 “= 44 “i 11 “  =34 ie 
Tf 5 36 > 26 “  =72 |13.5 “ =38 a 11 “« =31 os 
3. ofl B10) | 32 < =§5 ‘ 116.5 “ =44 ** 10 Oe 2 re 
LOS Guentao 748) ‘“ =74 oS | 16  =4] s PL Sy es = 29 = 
162) ot 140 SO O2-Dne 5 os 20 « =50 ee LE 29) s 
1 fe sed es etl ae 73 a 118 sc =44 sy 20D eer 0) ge 
PP Be|\ Cop NET oe 2 = 4 is 20 “ =43 = 12 =26 sr 
Ze SE ND) £ 6 =72 3 21 =42 ue 14 “« =28 ue 
Half shell... 53 ve “ =72 


ce 22 ce =49 ““ 13 cc =25 cc 


ORTMANN: SOUTH AMERICAN NAIADES. 537 


Remarks.—According to Simpson (1914), this form (gratus) is a variety of 
D. fontainianus (D’Orbigny), and there is no doubt that both are closely allied to 
each other. However, Simpson erroneously gives the distribution of fontainianus 
as: “Uruguay River and its affluents; Paranda River, southern Brazil,’’ while it 
is known only, according to D’Orbigny and Von Ihering (1893) from the Rio 
Parahyba, Rio de Janeiro, the upper Parand-drainage in Sao Paulo, and Lagoa 
Santa in Minas Geraes (Rio de las Velhas, Sao Francisco-drainage). In 1910 (p. 
138) Von Ihering drops this latter locality. Fontainianus has never been reported 
from the Uruguay. Thus it is not very likely that my specimens from this river 
are D. fontainianus, although they agree with it in some particulars. 

According to Von Ihering’s account of D. fontainianus (1893, p. 90, PL. 4, fig. 6), 
the latter differs from my specimens chiefly in having the posterior retractor- 
sear separated from the adductor-sear, but otherwise they are very similar. This 
holds good chiefly in the color of the epidermis. My specimens are greenish black, 
which agrees best with Von Ihering’s D. fontainianus, which is ‘‘black, with greenish 
basis,” and to a degree with D’Orbigny’s ‘‘brun noiratre,” while Lea describes his 
gratus as “dark olive brown.”’ The differences between D. gratus and D. fontaini- 
anus, as given by Simpson, concern the shape of the shell, which is said in gratus 
to be more wedge-shaped in front, and the texture of the epidermis, which is said 
to be smoother, subshining, and lighter in color. These differences I cannot 
recognize in my specimens. It is therefore hard to decide by which name they 
should be called. However, my specimens coming from the Uruguay River, 
being practically topotypes of gratus, I have concluded to call by this name, and, 
in order to avoid any misunderstanding, I have given a full description of them. 

Von Ihering (1893) believes that he has discovered sexual differences in the 
shell of D. fontainianus, the males being higher and shorter, and more rounded, 
the females being longer and more subtrapezoidal. Similar differences in shape 
are also noticed in our D. gratus. I have seventeen specimens in which the sex has 
been positively ascertained by examination of the gills, and I find that it is not 
possible to accurately determine the sex according to the shape of the shell. First 
of all, the two shapes are not sharply separated, but pass insensibly into each other, 
many specimens being intermediate between the two extremes. Besides, if form 
has any relation to sex, we may say that the highest shells (with the height of 79 
pr. et. of length and over) are, indeed, males; but among the others, having the 
height of 72 to 78 pr. ct. of length, there are as many females as males, and this ap- 
plies both to larger and smaller shells. It is true, that the average height of all my 
males is about 78 pr. ct., and the average height of all my females is 75 pr. ct.; but 


538 MEMOIRS OF THE CARNEGIE MUSEUM. 


these differences are so slight, that they do not furnish an exact criterion for the 
distinction of the sexes. 

Anatomy”.—The soft parts of eleven males and six females have been in- 
vestigated. 

Color of distal part of foot blackish, this color sharply set off from the pale 
basal part. Rest of soft parts whitish. Outer edge of anal opening (including 
the closed part) and of branchial, black; this color running forward beyond the 
branchial opening for a short distance. 

Anal opening closed above; closed part much longer than the open, the latter 
slit-like, a little shorter than the branchial opening, and separated from it by a 
solid mantle-connection. Branchial opening with small, but distinet papille. 
Palpi rather large for the size of the species, subtriangular, with curved lower 
margin; posterior margins connected only at base. 

Gills moderately long and rather wide. Outer gill with strongly convex lower 
edge, its widest part a little back of the middle, and about as wide as the inner 
gill in its posterior part. Anteriorly it becomes narrower, and its anterior end is 
near the highest point of the mantle-attachment-line. Inner gill with the inner 
lamina entirely connected with abdominal sac, its edge nearly straight in the an- 
terior part, where it is much wider than the outer gill. Anteriorly it is slightly 
narrowed, and its anterior end is immediately behind the palpi. Structure of 
non-marsupial gills (Pl. XLVIII, fig. 83a) somewhat unusual, with rather crowded, 
irregular interlaminar connections, forming weak, interrupted septa; these con- 
nections are more frequent toward the margins of the gills. Inner gill of the fe- 
male marsupial. Its interlaminar connections (Pl. XLVIII, fig. 3b) are more 
crowded, and heavier, arranged in interrupted rows running parallel to the gill- 
filaments, forming incomplete septa. The marsupium occupies only a part of the 
gill, leaving a small section at the anterior end free, a somewhat larger one (but 
hardly one-fourth) at the posterior end free also, so that the marsupium is located 
in the middle of the gill, and slightly more anteriorly than posteriorly. 

In this species, the structure of the marsupial and non-marsupial gills is more 
alike than usual as regards the arrangement and frequency of the interlaminar 
connections, but in the marsupium the connections are decidedly heavier and 
stronger, and form more distinet, although interrupted, septa (See Pl. XLVIII, 
figs. 3a and 3b). 

*0 The anatomy of D. fontainianus has been discussed by Von Ihering (1898, p. 90), but the finer 
structure of the marsupium has not been deseribed. The glochidia are said to be subtriangular, without 
hooks. Their length is 0.4 to 0.6 mm. Thus they are unusually large for the genus, and belong to the 


largest known among all Naiades. 


ORTMANN: SOUTH AMERICAN NATADES. 539 


26. DIPLODON DECEPTUS (Simpson) (1914) 


Shells: Plate XX XIX, figs. 1, 2, 3, 4, 5; Anatomy of gills: Plate XLVII, fig. 1; 
Section of gills: Plate XLVITI, fig. 4. 

Unio gratus Von InERING (non LEA), 1893, p. 92. 

Diplodon (Cyclomya) fontainianus deceptus Simpson, 1914, p. 1281. 

Type-locality.—Guahyba, Brazil. 

Other Locality.—Rio Guahyba, Porto Alegre, Rio Grande do Sul, Brazil (Von 
Ihering). 

Localities Represented in Carnegie Musewm.—Rio Guahyba, Porto Alegre, 
Rio Grande do Sul, Brazil (J. D. Haseman coll., January 24, 1909) two shells 
and one right valve (Topotypes). Rio Jacuhy, Cachoeira, Rio Grande do Sul, 
Brazil (J. D. Haseman coll., January 26, 1909) ten specimens with soft parts, 
males and females. 

Distribution.— Drainage of the Rio Guahyba and its tributary, the Rio Jacuhy, 
in Rio Grande do Sul. 

There is no question that my specimens belong to the form called by Von 
Ihering gratus, and by Simpson deceptus. Von Ihering compares his D. gratus 
with D. fontainianus, and says that the former much resembles the latter in shape, 
but that the epidermis of D. gratus is brown, shows radial sculpture, and is smoother; 
that the beaks are more anterior (24 to 31 pr. ct., average 27 pr. ct., against 29 to 
39 pr. ct., average 34 pr. et. in D. fontainianus); that the pseudocardinals of D. 
gratus are shorter and more stumpy; and that the posterior retractor-sear is always 
connected with the adductor-sear. 

All these characters hold good for my specimens, and they distinguish this 
form also from the real D. gratus of the Uruguay River, except that the location 
of the beaks does not differ so much (in true D. gratus it is 25 to 34 pr. ct.). 

Simpson’s D. deceptus has been described as being unevenly obovate, subin- 
flated, rather solid; pseudocardinals shorter, more stumpy, and much split. This 
also fits the present form, and I have no doubt that D. deceptus is the same shell 
as that called D. gratus by Von Thering. 

The chief differences between D. deceptus and D. gratus are the following: 

1. D. deceptus has a greater tendency toward the obliquely elongated shape, 
with subtrapezoidal or subovate outline. The height varies from 65 to 78 pr. ct. 
of the length, while in D. gratus it ranges from 72 to 85 pr. ct. 

2. The epidermis of D. deceptus is always brownish, with hardly any green in 
it, and not blackish green. It is smoother, since the fine concentric lines are not 


540 MEMOIRS OF THE CARNEGIE MUSEUM. 


lamellarly elevated (except indistinctly so near the margins), and the radial seulp- 
ture is more distinct, consisting of faint furrows, becoming often subscalariform 
toward the margins. 

3. The pseudocardinals of D. deceptus are more stumpy, chiefly in larger 
specimens. In younger ones this difference is not so marked, yet noticeable, when 
individuals of the same size are compared. In large specimens they are short 
and thick, chiefly so the posterior one of the right valve, and the anterior of the 
left (Pl. XX XIX, figs. le, 1d). The posterior one of the left valve generally is 
well developed, although smaller than the anterior one. All these teeth are split 
up into a number of denticles, and there are frequently accessory teeth, anteriorly 
in the left, and posteriorly in the right valve. 

All other characters are as in D. gratus, but D. deceptus grows to a larger size. 


MEASUREMENTS. 


No. |Sex Length, Height Diameter. | : Beaks. Figured. 
Cachoeira é | 

ile ? | 28 mm.19 mm. =68 pr. ct. of L.| 9 mm. =32 pr. ct. of L| at 8 mm. =29 pr. ct. of L. | 

4...) o'| 43 Py lse ii SS HLS25! ae UA = 13° "| =30 e Pl. XXXIX, fig. 3. 
6...| 9 | 47.5 35 ee we 19 =40 a 15“ -=31 cS | Pl. XX XTX, fig. 4. 
He allioe | 56 39.5 =71 22.5 =40 147 ee 2D) 4 
1 | 62 40 =65 ; 27.5 =44 17 =27 Pl, XXXIX, fig. 2. 
9...| 9 | 64 "143 = 64 26 =41 17 =27 

Porto Alegre 
2 AQ NST TG a 118.5 “ =38 12 =24 
4.. 55 43 “ =78 a 126 So aA 13 =24 | 


Remarks.—In this species we also observe higher and more elongated shells, 
nevertheless no relation between shape and sex is apparent. In fact, the most 
elongated specimen No. 11, H. 65 pr. et. (See Pl. XX XIX, fig. 2) is a male, and not, 
as might be expected (according to Von Ihering) a female. Altogether the number 
of individuals with the sex positively known is rather small, but the gradual transi- 
tion of the more elongated into the shorter and higher ones is evident. 

Anatomy.—¥ rom Cachoeira, I have the soft parts of three young specimens, of 
which the sex is not determined, and five males, and four barren females. 

Color of the distal part of the foot dark gray, this color sharply marked off 
from the whitish basal part. The rest of the soft parts whitish. 

Anal opening closed above; the closed part about four times as long as the 
open, which is slit-like, shorter (about three-fourths) than the branchial opening, 
and separated from the latter by-a solid mantle-connection. Branchial opening 
short, with small, but distinet, papillae. Palpi rather large, subtriangular, lower 
margins strongly convex, posterior margins with a short connection at base. 


ORTMANN: SOUTH AMERICAN NAIADES. 541 


Gills long and wide, posteriorly of about the same width, but anteriorly the 
inner is wider. Outer gill with margin curved, much narrower anteriorly, its 
anterior end near the highest point of the mantle-attachment-line. Margin of 
inner gill nearly straight in the middle, anteriorly this gill is a little narrowed, 
its anterior end immediately behind the palpi. Inner lamina of inner gill entirely 
connected with abdominal sac. 

Non-marsupial gills with scattered, short, interrupted interlaminar connec- 
tions, elongated in the direction of the gill-filaments. The marsupium of the 
female (pl. XLVII, fig. 1) is in the inner gill, leaving free a small anterior and 
posterior section, about one-fourth in front, and a little more behind, so that the 
marsupium is located in the middle of the gill, but slightly more anteriorly. The 
interlaminar connections (See also pl. XLVIII, fig. 4) are developed as rather 
regularly interrupted septa, forming intereommunicating, incomplete water-tubes. 
In the middle and at the base of the marsupium, the connections fall also into 
irregular transverse lines, with a suggestion of quincuncial arrangement. In 
young females, the marsupial part of the inner gill is considerably smaller. 

It should be noted that the non-marsupial gills in this species are more nearly 
normal than in D. gratus. 


27. DIPLODON ROTUNDUS Spix (1827). 


Diplodon rotundum and Unio rotundus Spix & WAGNER, 1827, p. 34, Pl. 25, figs. 3,4. 
Unio rotundus SowERByY, XVI, 1868, Pl. 72, fig. 369; Von InEeRING, 1890, p. 169, PI. 

9, fig. 10; 1910, p. 139. 

Diplodon (Cyclomya) rotundus Suwpson, 1900, p. 886; 1914, p. 1282. 

Type-locality—Southern Brazil. 

Other Localities —Rivers of eastern Brazil (Von Ihering, 1890); Rio S. Fran- 
cisco, Villa Nova, Sergipe, Brazil (Von IneRING, 1910); Rio Paraguassti, Bahia, 
Brazil (Von InertnG, 1893, p. 115; 1910); Rio Parahyba do Sul, Rio de Janeiro, 
Brazil (Von InERING, 18938, p. 115). 

New Locality.—Rio S. Francisco, Bom Jesus da Lapa, Bahia, Brazil (J. D. 
Haseman coll., December 17, 1907). Two odd right valves. 

In the Carnegie Museum there is another, complete specimen from the Hart- 
man collection without locality. 

Distribution. Known from the lower and middle part of the Rio 8. Francisco, 
Rio Paraguasst, and Rio Parahyba do Sul in eastern Brazil. 

According to the deseriptions given by Von Ihering and Simpson my specimens 
belong here, but my material is too scanty to give a full account of the species. 


542 MEMOIRS OF THE CARNEGIE MUSEUM. 


However, it should be said that of all species of the group this one most nearly ap- 
proaches the circular outline. It has been placed by Simpson, for this reason, in 
the subgenus Cyclomya, but, as has been indicated already by Von Ihering, there 
are specimens with the anterior part of the ventral margin less convex. The 
figures of the type (Spix and Von Ihering) clearly show the oblique shape of the 
shell, with the highest part more posterior, at, or behind, the posterior end of the 
ligament; and there is thus no question that this species falls into the same group 
with fontainianus and gratus. 

Von Ihering (1893, p. 93) emphasizes the separation of the anterior protractor- 
sear from the adductor-sear. In my specimens, this separation is not so distinct, 
but only partial, so that we must not lay too much stress upon this character. 


MEASUREMENTS. 


| 


Loc. Length. Height. Depth. | Beaks. Greatest Height. 
Bom | 
Jesus . 44 mm. 38 mm. =86 pr. et. of L.|20 mm. =45 pr. ct. of L.at 11 mm. =25 pr. ct. of L.at 27 mm. =61 pr. ct. of L. 
? 0O0 snl 4o0n Sor) 22.5°° =41 12.5 “ =23 34 e627 = 
Bom | | 
Jesus.'66 “ |57 “ =86 3 32“ =48 BS als =23 “ 41 “ =62 
(V.Lher. | 
1890)../38 “ 1382 “ =84 4 16) = —42 oe | 10 20 ra 


According to Von Ihering (1910, p. 139), this species reaches the length of 
75 mm. 

Subgenus: CycLtomya Simpson (1900). 

As has been stated, I restrict this subgenus to those shells which have a sub- 
rotund outline, with the greatest height located at about the middle of the shell, 
that is to say, vertically below the middle of the ligament. The posterior part 
of the shell is thus rather short, the shell is not obliquely subtrapezoidal, as in the 
species of the ellipticus-group, but rather pentagonal in outline. The species at 
hand is rather large and heavy, and belongs to the largest forms known in the genus. 


28. DrpLopon (CyCLOMYA) PARANENSIS (Lea) (1834). 
Shells: Plate XX XIX, figs. 6, 7. 

Unio paranensis LBA, Obs. I., 1834, Pl. 14, fig. 42; D’OrBrany, 1848, p. 603; 

SowERBY, XVI, 1866, Pl. 51, fig. 268; Cors1, 1901, p. 451. 
Diplodon (Cyclomya) paranensis Stupson, 1900, p. 887; 1914, p. 1284. 
Unio nocturnus Lea, Obs. X, 1863, Pl. 42, fig. 288. 
Diplodon (Cyclomya) nocturnus Simpson, 1914, p. 1285. 
Unio paraguayanus VON Martens, 1895, p. 34. 

Type-locality.—Rio Paranda. 


ORTMANN: SOUTH AMERICAN NAIADES. 543 


Other Localities —Rio Uruguay (D’Orbigny) (Lea, nocturnus); Rio Paranda up 
to above Corrientes (D’Orbigny); Rio Paraguay (Von Ihering, 1893, p. 119); 
Rio Paraguay, 25° S. Lat. (Von Martens) (This is near Asuncién, Paraguay). 

New Localities—Rio Paraguay, Corumbé, Matto Grosso, Brazil (H. H. 
Smith coll.). One large complete shell, one small left valve. In swamp of Lam- 
baré, five miles below Asuncién, Paraguay (J. D. Haseman coll., March 31, 1909). 
One right, one left valve. Rio de la Plata, San Isidro, Argentina (20 km. North of 
Buenos Aires) (A. Windhausen coll., January 1917). Five specimens with soft 
parts, males and barren females. 

Distribution.—Rio de la Plata, Paran’, and Paraguay, from near Buenos 
Aires up to Matto Grosso, Brazil; Rio Uruguay. 

Description of Shell.—Shell solid and rather thick, large (length up to and 
over 100 mm.). Outline angularly rounded, or broadly ovate, little oblique. 
Height generally over 80 pr. ct. of the length, rarely less (lowest figure known 76 
pr. ct., but this stands rather isolated, being found in a specimen measured by Simp- 
son). Valves closed, or very little gaping in front. Dorsal margin gently curved 
or straight (when young), descending anteriorly and passing into the anterior 
margin, without forming a distinct angle. Posteriorly the dorsal margin forms 
a more or less distinctly rounded angle with the posterior margin. The latter 
descends obliquely and is straight, or even a little concave; then it curves around 
in a sharp curve into the postero-ventral margin, this curve forming a blunt posterior 
point of the shell, well elevated above the basal line. The ventral margin has a 
sharp curve near its middle, forming a blunt, projecting angle at, or a little behind, 
the middle of the shell. The highest part of the shell is at 50 to 60 pr. ct. of the 
length. This ventral angle is generally distinct, but may be indistinct. From 
this projection the lower margin slopes upward in either direction, backward and 
forward, but the anterior part ascends more strongly, and is longer than the pos- 
terior, and is often almost straight part of the way, before it finally curves up into 
the anterior margin. The shell thus appears somewhat narrower anteriorly than 
posteriorly, and has a rounded pentagonal shape, the five angles being formed by: 
1, the beaks; 2, the upper posterior angle; 3, the posterior end; 4, the middle of the 
lower margin; 5, the anterior end. 

Valves not much swollen, moderately convex over the disk, but slightly flat- 
tened on both sides of a submedian more convex ridge. The latter runs toward 
the projection of the lower margin, but is very faintly marked. Posterior ridge 
rather distinct on account of a distinet radial depression behind it. This depres- 
sion makes the posterior slope much compressed, like a narrow wing. The slight 


544 MEMOIRS OF THE CARNEGIE MUSEUM. 


emargination of the posterior margin corresponds to this depression. Diameter 
40 to 46 pr. et. of the length (according to Lea’s figure a little less, about 38 pr. ct.) 
Beaks not swollen, and very slightly prominent beyond the hinge-line. Beak- 
sculpture variable, but always more or less heavy, covering from 15 to 27 mm. of 
the shell. There are about a dozen or more radial bars in front of the posterior 
ridge, of which the anterior and posterior ones are narrow, while those in the 
middle are thick and blunt. These ridges are very irregular; some anastomose, 
smaller ones may be intercalated between the larger ones, or they may be connected 
laterally. In some specimens the beak-sculpture is much less developed, but 
traces of the heavy ridges are always visible. Toward the lower margin, the beak- 
sculpture, when well developed, stops suddenly. In addition, there are upon the 
posterior slope a number of fine, oblique wrinkles, but these are only well-developed 
in young individuals. In the larger specimens there is a short lunula, which is 
narrow or very narrow. ; 

Epidermis smooth, but with numerous irregular concentric wrinkles, which are 
always crossed by more or less distinct radially impressed lines, forming here 
and there low ridges. Where the beak-sculpture is well preserved, it is seen that 
this radial sculpture is not a direct continuation of the beak-seculpture, but is in- 
dependent of it, beginning before the latter ends. In fact, the beginning of this 
sculpture causes, in part, the irregularities of the beak-sculpture. Color of epi- 
dermis yellowish brown to dark brown, generally darker posteriorly, without any 
distinet color markings. Sometimes there are greenish olive tints towards the 
beaks. 

Hinge-line gently curved. Ligamental sinus shallow, over the middle of the 
lateral teeth. Lateral teeth strong, moderately long, one in right, two in left 
valve, descending posteriorly. In the youngest specimens, the upper margin is 
somewhat elevated above the posterior ends of the laterals, while in the others 
it is less elevated, almost parallel to them. Pseudocardinals strong, ragged, com- 
pressed, running obliquely forward and downward, straight or curved. In the 
right valve there are two pseudocardinals, the posterior higher and stronger, 
much cut up. In the left valve there is one strong tooth, much cut up, and some- 
times a much smaller one behind it, which, however, may be absent. There is 
much variation in the raggedness of the pseudocardinals. i 

Cavity of beaks and shell rather shallow. Nacre whitish or lurid, iridescent. 
Anterior adductor-sear well impressed, subcireular, or subelliptical. Anterior 
retractor-sear small, rounded, above the adductor-sear and separated from it. 
Anterior protractor-sear rounded, connected with adductor-scar. Posterior ad- 


ORTMANN: SOUTH AMERICAN NAIADES. 545 


ductor-scar faintly impressed, almost pear-shaped, subovate or subtriangular, 
with an upper triangular process formed by the posterior retractor-scar. Mantle- 
line distinct, remote from the margin about one-fourth to one-fifth (or less) of the 
height of the shell. Dorsal scars about five (more or less), in beak-cavity in an 
irregular, longitudinal row, sometimes shifted a little toward the narrow hinge- 
plate. 


MEASUREMENTS.”! 


No. Sex. Length. Height. Diameter. Beaks at Greatest Height at Fig. 
% L. %L %L as Pl. 
Corumba . .. 45 mm.| 36 mm.=80 ! 20 mm.=44 16 mm. =36 ABP = yl SAPO 
Secicroeeen | eo le7Ometan|06), woke — en | oo | 6 =43 NN 20r flo =26 Soil fim 
Asuncioén ... peooe bs" 69 He Spill 34 a ) Diy SS «= 29 Ai — OL Pl. 
Solsidrovas..|° 2 86:5" © | 74.5. “* = 86: | 7336 A, Sf) HU Ue GV. 1). Ox) IE 
ID oserOl, «ees 90s 77 i= S0n KAO tome =) 145 PAR ies iets) Ape 50 f. 6 
Do. (eee) oe; Stil Wo <Uigh “ =85 | 42 —AG Ditto AT le — be 
Disses sinc pon. «< 8O a) Shey 39.5 “ =43 OA ie eT A) bye Se Sah) 
Corumba ... OG Ss Sl e441 te Dae 0) eee 
Lea’s figure .| ..| 86 “ 77 Ot) 33 a hey MO eet AG — es 
Simpsonesse|| 2. |) 92 7 78 *) =85")| 38 A el j 
Doomed. 22 sr LOO)! 76 Seen eA 7 i 
D’Orbigny..| ..|101 “ =86 =i 


Remarks.—Lea has described two other large, subrotund species from the 
Uruguay River: nocturnus and funebralis (Obs. X, 1863, Pl. 42, fig. 288, and Pl. 41, 
fig. 286). Of these, funebralis is similar in general shape and proportions, with 
the exception of the much greater compression of the valves. The diameter is 
only 30 pr. et. according to the figure and the measurements given by Simpson 
(1914 p. 1284), which falls far below of any of the measurements known for paranen- 
sis. In addition, in funebralis, the mantle-line is unusually far remote from the 
margin of the shell, and, according to our present knowledge, we must consider 
these characters as sufficient to separate the two species. 

U. nocturnus was united with paranensis by Simpson in 1900, but in 1914 
he separated them again. The proportions of nocturnus are: 


Length. Height. Diameter. Beaks. Greatest Height 


Lea's 

figure... 72 mm. 60 mm. =83 pr. ct. of L. 30 mm. =41 pr. et. of L. at 21 mm. =29 pr. et. of L. 
Simpson’s | 

measur. .|72 “ |60 “ =83 Se 28 “ =39 se | 


at 37 mm. =51 pr. ct. of L. 


Thus there is no essential difference from paranensis, and according to Simp- 

son’s account, I ean find only a difference in the color of the epidermis, which is 
b “ 

21 More care must be taken in this species than in others to place the ligament horizontally, and to 


measure parallel and vertical to it. The greatest height of the shell is hard to locate, and allowance 


should be made for this. 


546 MEMOIRS OF THE CARNEGIE MUSEUM. 


said to be bottle-green, almost black posteriorly, in nocturnus. I do not think that 
this is sufficient to separate nocturnus from paranensis, since in the latter olive- 
green tints may also be noticed. This is seen chiefly in a specimen from the Hart- 
man collection, without locality, preserved in the Carnegie Museum. Moreover, 
the original description of Lea’s paranensis mentions this color. 

The variability of the beak-sculpture of this species is remarkable. It has 
never been described in detail, except that it consists of rather heavy radial bars. 
In most of my specimens these bars are rather short (hardly more than 15 mm. 
long), but in three (all isolated valves, two from Asuncién, one young from Corum- 
ba) it extends farther, 25 to 27 mm., and chiefly in the young one (Pl. XXXIX, 
f. 7) this is very striking, since in this case the beak-sculpture extends over nearly 
half of the shell. I see, however, no other difference in these specimens, and even 
among them the bars are not uniform in length. I believe that U. paraguayanus 
Von Martens is founded upon such specimens. The dimensions of this fall easily 
within the range of variation of paranensis. According to Von Martens they are: 
length 102 mm.; height 82mm. = 80 pr. ct. of length; diameter 47 mm. = 46 per. ct. 
oflength. Thelocation of the beaks is given as “three-fourths of the length,” which 
probably corresponds to 25 pr. et. of length, we measuring from the anterior ex- 
tremity, the author having reversed the procedure. 

Von Martens compares his species with nocturnus, but says that it is larger, 
with stronger sculpture (meaning apparently the beak-sculpture), and larger 
hinge-teeth, but all these characters are unreliable, and do not distinguish it from 
paranensis. 

Anatomy.—The soft parts of two males and three barren females from San 
Isidro are at hand. 

Color whitish, distal part of foot gray. 

Anal opening closed above; the closed part being two to three times as long as 
the open, which is slit-like, and shorter than the branchial opening. Anal and 
branchial separated by a solid mantle-connection. Branchial opening with small, 
but distinct, papillae. Palpi subtriangular, lower margins curved, posterior margins 
connected for about one-third of their length. 

Gills moderately wide, posteriorly of about the same width, but anteriorly 
the inner gill is much wider. The shape of the latter is subtrapezoidal, that of 
the outer gill subtriangular. Anterior end of outer gill near the highest point of 
the mantle-attachment-line, that of the inner gill immediately behind the palpi. 
Inner lamina of inner gill entirely connected with abdominal sac. 

Structure of non-marsupial gills as usual, with few and scattered interlaminar 


ORTMANN: SOUTH AMERICAN NAIADES. 5A7 


connections. Marsupium of the female located in the inner gill, but not occupying 
all of it, leaving about one-fourth or a little less free at the anterior and the posterior 
end. In younger specimens the marsupial part is smaller, but also has a median 
position. Interlaminar connections of the marsupium forming interrupted septa, 
without any distinct transverse or quincuncial arrangement. 


Fina REMARKS ON THE GENUS DIPLODON. 


It is not claimed that the above arrangement of the species of Diplodon should 
be regarded as in any sense final. Even the two subgenera, Diplodon and Cyclomya, 
cannot be sharply separated: they are intimately connected with each other, 
and Cyclomya is allied with the ellipticus-group of Diplodon through species like 
rotundus, fontainianus, and gratus. The other groups cannot be very sharply 
defined according to shell-characters. It is to be hoped that the anatomy may 
furnish better criteria for the grouping of the species; but unfortunately not enough 
species are known from this point of view, and some of those known are not known 
fully enough. The characters of the glochidia need further special study. The 
following facts, however, may be emphasized: 

1. In six species of the chilensis-group (frenzeli, imitator, simillimus, vicarius, 
decipiens, paulista), the marsupium has a distinet tendency to move forward in 
the inner gill, and in three of these (simillimus, vicarius, paulista), it is entirely 
anterior to the middle of the gill. In five of these species, the structure of the 
interlaminar connections is interrupted septiform, or partly reticulate, but in one 
species (decipiens) continuous septa are formed. The glochidia of all these species 
have hooks. 

The tendency of the marsupium to move forward is found in addition only in 
two species of the ellipticus-group (gratus and deceptus). 

2. In the charruanus-group (charruanus, piceus, wruguayensis, hilde), the 
marsupium is rather large and lies in the middle of the gill; sometimes (hild@) it 
is smaller; and in two cases (charruanus and hild@) it has a tendency to move back- 
ward. In the lacteolus-group (two species, burroughianus and mogymirim), the 
marsupium is also located slightly more posteriorly. In most of these species, 
the interlaminar connections form interrupted septa, in part reticulated. But 
there is one exception, for mogymirim has continuous septa. This structure is 
thus only known in two species (mogymirim and decipiens) belonging to different 
groups. 

3. In the ellipticus-group, the marsupium may be in the middle of the gill 
(enno), slightly posterior (berthe), or slightly anterior (gratus, deceptus). Its 


548 : MEMOIRS OF THE CARNEGIE MUSEUM. 


structure may be prevailingly reticulate (berthew, enno), or prevailingly septiform 
(gratus, deceptus). 

4. D. paranensis has the marsupium in the middle half of the gill, and in- 
terrupted septiform structure is present. 

5. In eight species, hooks are known to be present on the glochidia. Of 
these six belong to the chilensis-group, one to the charruanus-group (piceus), one 
to the lacteolus-group (mogymirim). Glochidia without hooks (but possibly im- 
mature) were found in charruanus and berthe (charruanus- and ellipticus-groups). 
Two species have margined glochidia, hasemani of the hylwus-group, and hilde 
of the charruanus-group. 

For the present, these facts do not furnish any clue as to the relationship of 
the species or groups, they even are rather confusing, partly upsetting the divisions 
arrived at by the study of the shell. But they should be carefully recorded, 
because additional material may throw more light on the problem. 


Genus CASTALINA Von Ihering (1891). 


Von Thering, 1891, p. 478; 1893, p. 73; Simpson, 1900, p. 865; 1914, p. 1204. 

Type-species.—C. martensi Von Thering (designated by Simpson). 

The chief characters of this genus are found in the general shape of the shell, 
which is subtriangular or subquadrate, with a well developed posterior ridge and 
a subtruncated posterior slope, which, however, is somewhat elevated in the middle. 
In addition, the beaks are rather elevated, the interdentum is well developed, form- 
ing a rather deep beak-cavity. The hinge-teeth often are provided with parallel 
ridges. 

The anatomy is similar to that of Diplodon. However, there is a tendency to 
close the branchial opening in front, yet this is not always the ease, so that this 
character is variable, not only specifically, but also individually. 

The genus has been well treated by Von Ihering (1893), and a key for the 
species has been given (p. 83). Simpson (1914 p. 1205) also gives a key, but C. 
undosa should be excluded; it is a Castalia. 


29. CASTALINA NEHRING! Von Ihering (1893).” 
Diagram of soft parts: text-fig. 2, p. 456; Anatomy of gills: Pl. XLVI, fig. 2; Section 
of gills: Plate XLVITI, fig. 5; Glochidium: text-fig. 41, p. 469. 
Type-locality—Rio Piracicaba, SAo Paulo, Brazil. 


* Of both C. nehringi and martensi the specific names were first mentioned by Von Ihering in 1891 


(p. 477), but as nomina nuda without descriptions. 


ORTMANN: SOUTH AMERICAN NAIADES. 549 


Material Représented in the Carnegie Museum.—Rio Piracicaba, Sao Paulo, 
Brazil (Von Ihering, donor; cotypes or topotypes). Two specimens. Rio Tieté, 
Salto das Cruzes, Sio Paulo, Brazil (J. D. Haseman coll., September 22, 1908). 
Four specimens, two of them with soft parts. Rio Tieté, 25 miles above Itapura, 
Sao Paulo, Brazil (J. D. Haseman coll., September 27, 1908). Hight specimens, 
six of them with soft parts. - 

Distribution—Rio Tieté and Rio Piracicaba in Sao Paulo, headwaters of Rio 
Parana. 

Von Ihering has given a detailed description of this species, pointing out its 
differences from the allied species. He believes that specimens with the beaks 
more distant from the anterior margin are males. I cannot control this, since I 
have no males among those of my specimens with soft parts, but the percentage 
eiven for the location of the beaks in the males (28 to 30 pr. ct.) 1s not represented 
in my measurements, and this would tend to confirm Von Thering’s observation. 
It is to be noted that my smallest specimens (Nos. 1 to 5 from Itapura) exceed in 
height the figures given by Von Ihering, and thus young shells are proportionally 
higher: the older ones become longer on account of a prolongation of the posterior 
end of the shell (best seen in No. 6 from Itapura). 


MEASUREMENTS. 


|No. Sex. Length. | Height. | Diameter. | Beaks. 


LUShop es Go igk Bake cs] wel (ES | 51 mm.46 mm. =90 pr. ct. of L.'26 mm. =51 pr. ct. of L.lat 9 mm.=IS pr. ct. of L. 
1B Yo}: Paras Ageia’ Semone =86 - 29.5 Ss, e 11 20 oe 
IDs Scare soe. Secs ey =87 t |26 =47 | 10.5 =19 
Salto das Cruzes..... 1/Q =80 31 =50 |) e12 =20 
Do. Fas : DEO =80 34 =49 15 =22 
Tapura.t 8 ev eee 16/9 “"=79 ‘40 =49 15.5 =19 


Anatomy.—I have the soft parts of eight specimens, all of which are females, 
three of them gravid. One of the latter had eggs; one had immature, and the 
third mature glochidia. For the breeding season the dates of collection (September 
22 and 27) should be noted. (Mature glochidia were found on Sept. 22.) 

Von Ihering (1893, p. 79) describes the soft parts of two males. Of these, 
one had the branchial opening closed in front, the other open. This is the species 
of Castalina, to which I have referred previously (Ortmann, 1911, p. 118). In 
none of my females is there an anterior mantle-connection in front of the branchial 
opening. Therefore this seems to be the normal condition in this species, although 
it should be born in mind that this connection at its best is very slight, and might 
be easily torn by rough handling. 

The anal opening is described by Von Ihering as also differing in his two 


550 MEMOIRS OF THE CARNEGIE MUSEUM. 


specimens. He mentions the presence in one of a supra-anal opening; but is not 
quite positive that this is natural. According to my material, the anal is always 
closed above, without forming a supra-anal (text-fig. 2,s, p. 456). The soft parts 
have the following characters: 

Anal opening closed above; open part (text-fig. 2, a p. 456) short, somewhat 
shorter than the branchial, slit-like, its inner margin indistinctly crenulated or 
smooth. Closed part (s) about three to four times as long as the open part. A 
supra-anal canal extends all the way under the closed part (above the rectum), 
ending blindly above. Mantle-connection between anal and branchial openings 
well developed (text-fig. 2, 1). Branchial opening (b) with well developed papillz 
on inner margin, which show some irregularities at the anterior end of the opening, 
but in none of my specimens are distinct traces of a connection of the mantle margins 
in this region visible. Palpi (h) large, subtriangular, almost faleiform, with long 
and curved lower margins, and short posterior margins, the latter connected for 
about one half of their length. 

Gills (text-fig. 2, 7, 0) moderately wide, the inner (7) distinetly wider, chiefly 
anteriorly. Outer gill (0) with gently curved edge, its anterior end near the highest 
point of the mantle-attachment-line. Inner gill with the edge almost straight, 
anteriorly alittle narrower, and broadly attached, the attachment occupying all 
of the space between the anterior end of the outer gill and the palpi (hf). Inner 
lamina of inner gill entirely connected with abdominal sac. In the female (PI. 
XLVI, fig. 2) the inner gill is marsupial, but only a section of the gill possesses this 
character, with the interlaminar connections distinctly arranged in interrupted 
septa (See also Pl. XLVITI, fig. 5). The marsupial part is rather small in younger 
specimens (such as the one figured on Pl. XLVII, fig. 2), lying immediately behind 
the middle of the gill; but it is larger in older specimens, lying practically m the 
middle, leaving free about one-third anteriorly as well as posteriorly (text-fig. 2, 7). 
The non-marsupial gills have remote, incomplete, interrupted septa, and the septi- 
form structure is more evident than it generally is in Diplodon (See outer gill, 
PL XLVIL, fie). 

When charged, the eggs or glochidia do not form placenta-like masses. The 
fully developed glochidium (text-fig. 4,1, p. 469) is subtriangular, with a lower point 
situated about in the middle of the lower margin, and with distinct hooks at this 
point, which differ from those seen in certain species of Diplodon in that they are 
shorter, and broader at the base. L. 0.26 mm.; H. 0.24 mm.; hooks: 0.06 mm. 


Thus the glochidium is rather small. 


ORTMANN: SOUTH AMERICAN NAIADES. 551 


30. CASTALINA MARTENSI Von Ihering (1893). 

Von Thering, 1893, p. 81, Pl. 3, fig. 5; Simpson, 1900, p. 865; 1914, p. 1205. 

Type-locality.— Rio Camaquam, Rio Grande do Sul, Brazil. 

New locality.—Rio Jacuhy, Cachoeira, Rio Grande do Sul, Brazil (J. D. Hase- 
man coll., January 27, 1909). Three complete shells and one right valve. 

Distribution.—Our new locality extends the range of this species northward. 
The Rio Jacuhy belongs to the Guahyba-system, but both the Guahyba and Cama- 
quam flow into the Lagoa dos Patos. Von Ihering says that he did not find this 
species north of the Rio Camaquam. 

This species has been sufficiently well described by Von Ihering. Our youngest 
specimen shows well developed beak-sculpture, corresponding to the description. 
The variations mentioned by Von Ihering in the crenulation of the lateral teeth 
are also seen in our specimens. 


M®8ASUREMENTS. 


Length. | Height. Diameter. Beaks. 


26mm. = 21.5 mm.=83 pr. ct. of L.. 13.5 mm. =52 pr. ct. of L.. at 8.5 mm.=33 pr. et. of L. 

48 * 38 i = 7G c 24 “c —50 ““c 12 “ Or “c 

AS Oto, ae 84 20: ate = 54 ~ 13 i 

75 155 ‘79 “ 34 «  =45 Uk 21 ne Largest speci- 


| men of Von [hering) 


The height ranges according to Von Ihering from 70 to 79 pr. ct., and the diam- 
eter from 45 to 50 pr. ct. The location of the beaks is from 21 to 29 pr. ct. Thus 
our specimens are comparatively higher and more swollen. As far as concerns the 
height, this is certainly due to the smaller size of my shells, since a similar change 
in the proportional height with age has been observed in C. nehringi. 

Anatomy.—Of this species Von Ihering (1891, p. 477) says that in most cases 
(seven out of eight) the branchial opening is closed in front. I do not possess the 


soft parts. 
31. CasTALINA PSAMMOICA (D’Orbigny) (1835). 


Unio psammoica D’OrBIGNyY, 1848, p. 608, Pl. 71, figs. 4-7; SowerBy, XVI, 1868, 
Pl. 93, fig. 507. 

Castalina psammoica Von InmrinG, 1893, p. 79; Von Marrens, 1894, p. 164; 
Smmpson, 1900, p. 866; 1914, p. 1206; Haas, 1916, pp. 9, 47. 
Type-locality.—Rio Parana, Itaty, above Corrientes, Argentina. 

Other Localities —Province Santa Fé, Argentina (D’Orbigny) (farther down the 
Parana); Rio Paraguay, near mouth of Rio Apa (Von Ihering) (in Paraguay, at 
Brazilian boundary); Paraguay (Von Martens); Rio Uruguay, Salto Oriental, 
Uruguay (Haas). 


ae MEMOIRS OF THE CARNEGIE MUSEUM. 


New Localities.—Rio Uruguay (in mud), Uruguayana, Rio Grande do Sul, 
Brazil (J. D. Haseman coll., February 5, 1909). One young male with soft 
parts. Rio de la Plata, San Isidro, 20 km. north of Buenos Aires, Argentina (A. 
Windhausen coll., January 1917). One male with soft parts. 

Distribution.—From the La Plata near Buenos Aires up to the Rio Parana and 
Rio Paraguay in Paraguay, and also in the Rio Uruguay. 

The descriptions given by D’Orbigny, Von Ihering, and Simpson agree well 
with our specimens, but it should be mentioned that the beak-sculpture sometimes 
covers less than half of the adult shell. The hinge-teeth are very variable, but 
Von Ihering’s account represents the normal condition. The laterals are said 
to be smooth or finely smoothly striated. In my young specimen they have dis- 
tinct, vertical, irregular, and granular ridges; in my larger specimen they are ir- 
regularly granular and crenulated, but have no distinct vertical ridges. 

According to Von Ihering, the maximum length is 70 mm.; according to D’Or- 
bigny, 75mm. The height according to the former is 77 to 80 pr. ct.; according to 
the latter, 76 pr. ct.; the diameter is 50 and 49 pr. ct. respectively. The beaks are 
located, according to Von Thering at 17 to 23 pr. ct. of the length. 


MEASUREMENTS. 
Localities. | Sex | Length. | Height. Diameter. | Beaks. 
lOhgirare ant yc aestsic | rofl 44 mm. | 35 mm. =80 pr. ct. of L. |23 mm. =52 pr. ct. of L.lat 10.5 mm. =24 pr. et. of L. 
San isidroess. i726 ete lo 6278 5 z 


50, Peay See 875) LSet seas 


Thus our larger specimen is unusually swollen. 

Remarks.—This species somewhat resembles the genus Castalia, chiefly on 
account of the strong development of the beak-sculpture. However, according to 
the posterior slope, which is distinctly elevated along the upper posterior margin, 
and also according to the structure of the lateral teeth, which have the vertical 
ridges poorly, or not at all, developed, it isa Castalina. In Castalia furthermore the 
diameter of the shell generally is much greater than the maximum (60 pr. ct.) ob- 
served in the present species. 

Anatomy.—Soft parts of two males at hand. Color whitish. 

Anal opening slit-like, closed above; closed part three to four times as long as 
the open, the latter shorter than the branchial opening, and separated from it by 
a solid mantie-connection. Branchial with small papille. In the smaller specimen, 
the branchial opening is closed in front by a firm union of the mantle-margins, 
but in the larger specimen there is no such connection, and thus in this species 
this character is variable. Palpi rather large, nearly subfalciform, with the lower 


ORTMANN: SOUTH AMERICAN NAIADES. 553 


margins long and strongly curved, posterior margins short, and united at base for 
about one-fourth of their length. 

Inner gills much wider than the outer, chiefly in front; only for a short 
distance behind have they an equal width. Outer gill with curved margin, anterior 
end at highest point of mantle-attachment-line. Inner gill with margin nearly 
straight, broadly attached anteriorly, and anterior end close to the palpi. Inner 
lamina of inner gill entirely connected with abdominal sac. Structure of non- 
marsupial gills normal, with scattered interlaminar connections, assuming here and 
there the shape of short, weak septa. 


Genus CASTALIA Lamarck (1819). 


Castalia LAMARCK, 1819, p. 66; PrusBpry, 1911, p. 610. 
Tetraplodon Srrx, 1827, Pl. 25; Pinspry, 1893, p. 90; Srmpson, 1900, p. 863; 1914, 

p. 1194. 

Pilsbry (1911) has brought to light the fact that Savigny’s genus Castalia 
(Vermes) is not to be dated from 1817, but that it is later (certainly not before 1820, 
probably as late as 1826), so that Castalia applied by Lamarck (1819) to the present 
genus has to stand. 

Castalia is distinguished by the triangular outline, with high beaks, well de- 
veloped posterior ridge, great obesity of the shell, truncated posterior slope, and 
well developed beak-sculpture, which extends over a large part of the shell. It 
is to be noted, however, that the truncation of the posterior slope often varies with 
age, so that in very young specimens it is somewhat elevated in the middle, giving 
an outline to the shell approaching the subtrapezoidal or subrhomboidal. With 
one exception the species resemble each other very closely. This exception is 
C. undosa, which differs from all the rest in having strong, oblique folds, or ribs, upon 
the posterior slope. 

My material of Castalia is rather insufficient, and I have had great difficulties 
in determining the species. The key given by Simpson (1914) is useless for the 
reason that the type-species (ambigua) has been misunderstood. The latter has 
been redescribed and figured by Von Ihering (1910),”° which fact had been neglected 
by Simpson. At the same time Von Ihering has given an elaborate key for the 
species. However, this also is unsatisfactory, and I am afraid that Von Ihering 
has not paid proper attention to the changes undergone by the shell with advancing 

23 In this connection it should be mentioned that Wyatt, T. (A Manual of Conchology, 1838, p. 65, 
Pl. 11, fig. 5) has given a recognizable figure of C. ambigua, which undoubtedly represents the genuine 


ambigua, as determined by Von Ihering). 


554 MEMOIRS OF THE CARNEGIE MUSEUM. 


age. In trying to use this key, I generally met with the difficulty that my specimens 
were intermediate between the alternatives given in it. But, as I said, my material 
is too scanty to bring order out of this confusion, yet I shall try my best to give an 
account of the material at hand. 

The geographical distribution of the species of this genus is interesting. Ac- 
cording to Von Ihering (1910, p. 130) their metropolis is in the Amazon-drainage, 
whence the forms extend into Guyana and the upper Parand-drainage. But on 
account of the great uncertainty prevailing with regard to the various species no 
details can be given. 


32. CASTALIA ACUTICOSTA Hupé (1857). 
Glochidium: Text-fig, 4, m, p. 469. 
Castalia acuticosta Hurt, 1857, p. 77, Pl. 14, fig. 3; SowersBy, XVII. 1869, Pl. 3, 

fig. 12. 

Tetraplodon acuticosta VON TH ERING, 1910, p. 128. 

Type-locality—Brazil. (Von Ihering says that Castelnau collected this 
species In Goyaz, but I cannot find this fact mentioned in Hupé’s paper.) 

Other Localities—Rio Araguay, Goyaz, Brazil (Von Ihering, 1910, p. 135); 
Lagoa do Coral, Goyaz, Brazil (Von Ihering) (drainage of Rio Araguay, tributary 
to Tocantins). 

New Localities.—Sand-bar of Rio Tapajos, Santarem, Para, Brazil (J. D. Hase- 
man coll., December 6-12, 1909). Eight specimens, one of them a male with soft 
parts. Center of Rio Guaporé, near Rio Sao Simao, Matto Grosso, Brazil (J. D. 
Haseman coll., July 20, 1909). Three specimens, with soft parts, male, and gravid 
females. Rio Guaporé, Sao Antonio de Guaporé, Matto Grosso, Brazil (J. D. 
Haseman coll., July 31, 1909). Four specimens. Rio Machupo, San Joaquim, 
Bolivia (J. D. Haseman coll., September 1, 1909). Three young specimens, with 
soft parts, probably males. 

In addition, the Carnegie Museum possesses a fine specimen from the Juny 
collection, without locality. 

Distribution.—Southern tributaries of the Amazon, from Tocantins and Ara- 
guay in Goyaz, and Rio Tapajos in Para, to the Madeira (Guaporé and Machupo) 
in Matto Grosso and Bolivia. 

This species belongs to those with elevated beaks, although the beaks are here 
far less prominent than in turgida, baro, and hanleyana. It is a small species 
(maximum length 35 mm.); but that specimens about 25 mm. long are mature is 
shown by the fact that at that size they may be gravid. 


ORTMANN: SOUTH AMERICAN NATADES. 555 


The outline is “subquadrate” according to Von Ihering. I should call it 
rather subtrapezoidal or subrhomboidal, and this is due to the fact that the pos- 
terior end is not much produced, and that the angle between the upper and the 
posterior margins is somewhat prominent; consequently, the posterior slope is 
not so much truncated as in other species, but a little elevated toward the upper 
posterior angle. On account of the shortness of the shell, the beaks are com- 
paratively remote from the anterior end. 

Von Ihering has pointed out that there are variations in the beak-sculpture, 
and I observe this also in my specimens. In most cases it is sharp, the bars are 
narrow and distinct, aad extend to the lower margin of the shell. But sometimes 
the bars are more rounded, less distinet, and may not reach the lower margin. A 
few finer radial bars are generally present upon the posterior slope. 


MEASUREMENTS. 


Loealities. | No. Sex Length. | Height. Diameter. | Beaks 


Santarem........... pa ie | 18.5 mm.16 mm. =86 pr. ct. of L. 14 mm. =76 pr. ct. of L. at 5.5 mm. =24 pr. ct. of L. 
LD pec eae 3\/o | 20 sel pt Ie 90 3 Hré A G5 es G83" 54 3 = 
Gnaporele aoe is oes 2h Onl tee | 20a SS cu 19 =79 6.5 =27 
WOO Shree Marches ies. <5 1 | 9 | 24 * j20:0 —~ =8) a 18 =75 6 =25 
LD Wee Seer Siloti eS newbs ass ‘ Bail Wes eed, ts =29 
Santaremy. 2.5... - | 6 |? | 29 “ 125 “ =86 es 22 =76 8.5 =29 
10” ys ee ei 2 | 30 ee tau ““ =90 S 23 =77 | 10 =33 
Hupé, text-figure..... | 3 =68 


Baie 2S bee S767 S 2: 


It should be remarked that Hupé’s figure of the diameter (half shell) does 
not agree with his measurements in the text. This figure would give a diameter 
of only 18 mm. (= 53 pr. ct.,) while the text gives 68 pr. ct. Both height and diam- 
eter of Hupé’s shell are less than in any of mine. Von Ihering gives the location of 
the beaks at 39 to 41 pr. et. of the length, which is much greater than the figures 
of Hupé (31 pr. ct. according to the figure) and of my shells. But I believe that this 
discrepancy is due to a different way of measuring: I always measure parallel to 
the ligament. 

Remarks.—My specimens certainly belong together; but I am not quite positive 
that they might not be only the young stage of some other species (hanleyana or 
baro). The fact that some of mine are gravid does not demonstrate that they are 
adult or nearly adult, for we know that other Naiades become sexually mature, 
when yet rather small. The further fact that those from Santarem were found 
associated with baro and hanleyana indicates that they may belong to these species. 
However, I am unable to decide this question. 

Anatomy.—Soft parts of two males and two gravid females (with glochidia) at 
hand. The latter were found on July 20. Color of soft parts whitish. 


556 MEMOIRS OF THE CARNEGIE MUSEUM. 


Anal opening slit-like, closed above; closed part about four to five times as 
long as the open, the latter separated from the branchial opening by a solid mantle- 
connection. Branchial opening with small papille, closed in front by a mantle- 
connection in the two males and in one of the females, while in the other female 
this connection is missing (but it may be torn). Palpi moderately large, sub- 
triangular, with curved lower margins, and the posterior margins united for about 
one-fourth of their length. 

Gills about equally wide posteriorly, anteriorly the inner is the wider, of the 
usual shape. Inner lamina of inner gill entirely connected with the abdominal 
sac. Non-marsupial gills with scattered interlaminar connections. Marsupium 
in the middle of the inner gill, leaving about one-fourth of the gill free at the anterior 
end, and a little less at the posterior. Interlaminar connections interrupted, but 
their arrangement cannot be clearly seen, since no barren females are at hand. 

Glochidium (text-fig. 4, m, p. 469 ) subtriangular, with a point at about the 
middle of the lower margin, and with hooks of the usual shape, but rather short. 
L. and H. about 0.24 mm., hooks 0.05 mm. Thus the glochidium is rather small. 


33. CASTALIA HANLEYANA Sowerby (1869). 


Castalia hanleyana Sowrersy, XVII, 1869, Pl. 1, f. 5. 
Tetraplodon hanleyanus Von THerina, 1910, p. 127. 

Type-locality—-Unknown. 

Other Localities —Rio Araguaya, Ilha Bananal, Goyaz, Brazil (Von see 
State of Pari, Brazil (Von Ihering). 

New Locality.—Sand bar of Rio Tapajos, Santarem, Parad, Brazil (J. D. Hase- 
man coll., December 6-12, 1909). Two odd valves (right and left). 

Distribution.—It should be noted that this species is found, where also acuti- 
costa occurs, in the Rio Araguaya and the Rio Tapajos. 

My two valves agree well with the account given by Von Ihering, and with 
Sowerby’s figure, but are smaller than the latter. 


MEASUREMENTS. 


Length. Height. Diameter. | Beaks. 


42.5 mm. 35 mm. =82 pr. ct. of L. 28 mm. =66 pr. ct. of L. | at 12 mm.=28 pr. ct. of L. 
36.5“ Sie = Bae 1, A= ee [0.5 28 


Remarks.—According to Von Ihering, the beaks are at 30 to 33 pr. et., while my 
specimens show lower figures. But this fact may be due to a different way of 
measuring. The shell is characterized by high beaks and its high, triangular (not 


ORTMANN: SOUTH AMERICAN NAIADES. 557 


elongated) shape, which makes the beaks appear to be rather far back (in comparison 
with baro). However, this may be only a more aged form of acuticosta. 


34. CasTauiaA BARO (Von Ihering) (1910) 
Castalia ambigua SowERBY (not LamMARcK), XVII, 1869, Pl. 1, fig. 1. 
Tetraplodon baro Von THErRING, 1910, p. 127; Stmpson, 1914, p. 1198. 
Type-locality Amazon River. 
New Locality: Sand bar of Rio Tapajos, Santarem, Parad, Brazil (J. D. Hase- 
man coll., December 6-12, 1909). One complete shell, two odd valves, right and 


left. 
In addition the Carnegie Museum has two other fine specimens, one from the 


Holland collection, labeled ‘River Amazon,” the other from the Juny collection, 
without locality. : 

Distribution: Amazon and Tapajos Rivers. 

This species stands very close to C. hanleyana, and differs only in its more 
elongated shape, and, consequently, more anterior beaks. Von Ihering says that 
the lower margin is straight (while it is convex in hanleyana). But this feature is 
somewhat variable, for it may be gently curved. However it is correct that in 
baro the lower margin is more nearly straight than in hanleyana. 

I should not be astonished if hanleyana and baro should finally prove to be 
only the adult stages of acuticosta. The fact that all three have been found by 
Haseman associated at Santarem is in favor of this view. 

About the dimensions of baro we only know that the beaks are at 16 pr. ct. of 
the length. My specimens show a somewhat higher percentage, but not as high 
as in hanleyana (where it is from 28 to 33 pr. ct.). 


MEASUREMENTS. 


Localities. | ength. | Height. 


Diameter. Beaks. 


Santarem../39 mm. 28 mm.=73 pr.ct. of L. 27 mm.=69 pr. ct. of L.) at 9 mm.=23 pr. et. of L. 
oe ~ ‘ 6 0 ae 


iDlog mone ean oe 8} =73 “ 30.5 “ =67 é g9 “ =2 
Armaan Sere Some 03 uf: Soke 8 = 67 es OSS ae? 
(uny)ic..shees “39.5 -=75 et sien at = 79 « 10 “ =19 «“ 
Santarem..155 “ |40 “ =73 « 36. « =65 ee ey Mt ee “ 


35. CASTALIA PECTINATA (Spix) (1827). 
Tetraplodon pectinatum Sprx, 1827, Pl. 25, fig. 3; Von Inerina, 1910, p. 125. 
Unio pectinatus WAGNER, 1827, p. 32. 
Castalia ambigua Von InERING (not LAMARCK), 1890, p. 162. 
Type-locality.—Rio Sao Francisco, Minas Geraes, Brazil. 


558 MEMOIRS OF THE CARNEGIE MUSEUM. 


New Localities —Amazon River, Pard, Brazil (Hartman collection). Two 
specimens. Sand bar of Rio Tapajos, Santarem, Parad, Brazil (J. D. Haseman 
coll., December 6-12, 1909). One odd (right) valve. 

Distribution.—Known hitherto orily from the Rio Sao Francisco, and only 
from the description and figure of Spix and Wagner. Its discovery in the Amazon 
and Tapajos in Parad thus extends its range into the lower basin of the Amazon. 

The characters of this species have been established by Von Ihering, and, 
although it is hazardous to define an old, often misunderstood, and poorly figured 
form, without having abundant material, the fact that our specimens well agree 
with the account given by Von Ihering, demonstrates that he is right. The chief 
characters of this species are found in the low beaks, the rather elongated outline, 
and rather anterior position of the beaks. The beak-sculpture is described as 
“mostly”? reaching the ventral margin. This is actually the case in one of our 
specimens from the Amazon and in the half shell from the Tapajos. In the other 
individual from the Amazon the radial bars are shorter and cover only a little 
more than half of the shell. 


MEASUREMENTS. 

Locality. | Length. Height. | Diameter. | Beaks. 
Amazon...| 28 mm. |.21.5 mm.=77 pr. ct. of L.. 17 mm.=61 pr. et. of L. | at 6 mm.=21 pr. et.of L 
Mapajos® 2423) a. 21 ye .: 18 “ =64 “ 6.5 “ =23 sf 
Amazon...| 31 “ | 23 « =74 S al - 


“ce 20 “ce =6§5 a 8 


Remarks.—Von Thering gives the location of the beaks as 25 pr. et.; my speci- 
mens agree with this very well. 

C. juruana (Von Thering, 1910, p. 126) from the Rio Jurua (southern tributary 
of the Amazon in western Brazil) is closely allied. It is founded upon a single 
specimen, which differs chiefly in the location of the beaks (at 37 pr. et.), and certain 
other characters, which at least in part are connected with this. It may finally 
prove to be only a form of pectinata. 

Our specimens have about the size given by Wagner in the text (l. ¢., p. 33) 
28 to 31 mm.; while Spix’s figures (Pl. 24, figs. 3, 4) are considerably larger (L. 
over 40 mm.). Thus they apparently are enlarged. C.juruana is larger, L. 46 mm. 


36. CASTALIA INFLATA D’Orbigny. (1835). 
Castalia inflata D’OrBrIaNy, 1835, p. 43. 
Castalia ambigua D’OrBIGNY, 1848, p. 598, Pl. 72, figs. 4-6. 
Castalia ambigua inflata VON IHERING, 18938, p. 88. 
Castalia quadrilatera VON IHERING, 1893, p. 89. 


ORTMANN: SOUTH AMERICAN NAIADES. 559 


Tetraplodon inflatus Von InerinG, 1910, p. 126; 1915, p. 12. 

Type-locality—Parana River, Corrientes, Argentina. 

Other Localities —Lower Paranda River (Von Ihering); small tributaries of the 
Parana (D’Orbigny); Rio Paraguay, near Rio Apa, Paraguay (Von Ihering); Rio 
Paraguay, San Luis de Caceres, Matto Grosso, Brazil (Von Ihering). 

Locality Represented in Carnegie Museum.—Rio Paraguay, San Luis de Caceres, 
Matto Grosso, Brazil (J. D. Haseman coll., May 24, 1909). Two specimens. 

Distribution.—Positively known only from the Parand and Paraguay Rivers in 
Argentina, Paraguay, and Brazil. Specimens reported from the Amazon-drainage 
in Bolivia probably do not belong here. 

My identification of this species depends partly on Von Ihering’s key, partly 
on D’Orbigny’s original description and figures of specimens from Corrientes, 
and on the locality. It is a species with low beaks, the shell is oval, but for the 
rest, Von Ihering’s key is insufficient. One of my specimens is rather small, and 
the beak-sculpture reaches the lower margin; in the other, it falls short of it. The 
beaks are located at 21 and 24 pr. ct. (21 pr. et. given by Von Ihering). The shell 
is about as long as in pectinata, and is thicker. The bars of the beak-seulpture 
in my specimen are rather numerous, but not very sharp. The adductor-scars 
agree with Von Ihering’s account. Thus I have no doubt that my specimen repre- 
sents C. inflata, although the essential characters of this species are yet obscure. 


MEASUREMENTS. 
: | Length. | Height. Diameter Beaks. 
29 mm. |23 mm. =79 pr. ct. of L.20 mm. =69 pr. ct. of L. at 6 mm. =21 pr. ct. of L 
|}36 * |26 =72 3 22.5 “ =63 ss 8.5 =24 a 
DtOrbignys texts wets a2 Gomer 75 | 60 
D’Orbigny’s fig. of specimen | | 
from Corrientes........---- Bis) A Pe - 24 0 8.5“ =24 


Von Ihering does not give detailed measurements, but only says that the maxi- 
mum length is 51 (1893) and 60 mm. (1910). 


37. CasTaLiA UNDOSA Von Martens (1885). 
Shell: Plate XX XIX, figs. 8a-d. 
Castalia undosa Von Martens, 1885, p. 148; Von Inerina, 1893, p. 84; NEHRING, 
1893, p. 165. 
Castalina undosa Stupson, 1900, p. 866; 1914, p. 1207. 


Tetraplodon undosus ORTMANN, 191 1a, p. 117, Pl. 6, fig. 7, Pl. 7, fig. 7 (anatomy). 
Type-locality.—Rio Piracicaba, Piracicaba, Sao Paulo, Brazil. 


560 MEMOIRS OF THE CARNEGIE MUSEUM. 


Localities Represented in Carnegie Musewm.—Rio Piracicaba, Sao Paulo, 
Brazil (Von Ihering donor, authentic specimens). One complete shell and one 
odd (left) valve. Rio Tieté, silty river banks, twenty-five miles above Itapura, 
Sao Paulo, Brazil (J. D. Haseman coll., September 27, 1908). Four specimens 
with soft parts, one male and three females. Rio Tieté, Itapura, Sao Paulo, Brazil 
(J. D. Haseman coll., September 28, 1908). Five specimens, one of them a male 
with soft parts. 

Distribution.—Rio Tieté and Piracicaba of Upper Parand-drainage in Sao 
Paulo, Brazil. 

This species has been well described by Von Martens and Von Ihering, and I 
do not need to add anything, except that the dimensions vary considerably, the 
height from 71 to 86 pr. ct. and the diameter from 53 to 66 pr. ct. of the length. On 
the average our specimens are more swollen than the previous measurements would 
indicate. The most characteristic feature of this species is the quite unique de- 
velopment of the ribs of the posterior slope, which are much stronger than the 
oblique ‘‘wrinkles’’ often found in species of Diplodon. 

Simpson has put this species in the genus Castalina, but I do not see any 
reason for this. The posterior slope undoubtedly has the characters of Castalia. 
The species, indeed, stands isolated in the genus, and cannot be confounded with 
the other species, and for this reason, probably, Von Ihering omitted it in his key 
(1910). 


MEASUREMENTS. 
No. |Sex Length. Height. Diameter. | Beaks. < Figure. 
? 42 mm.'34 mm. =8I pr. ct. of L.26 mm.=62 pr. ct. of L.at 10 mm. =24 pr. ct. of L.|/Pl. XX XIX, 
Fe .| 2 146.5 “ |39 So a Set 3 27 “ =58 a 11.5 =25 r fig. 8. 
B35. 2 |47 PE NEY (ya) =S80 cs 31 =66 = 11.5 =24 
Cathie 9 \51 “138.5 =75 31 =61 13 =25 = 
a. oo 57 “44 —lC/ 33.0 ~ =59 z 13.5 =24 S 
o |60 mee Hic =78 36 =60 ; 14 =23 4 
(Von 
Martens).. 56 “148 “ =86 30 =53 2/7 =29 : 
(Von Thering) | 66 SOL “" =76 ? 36 “ =55 


Anatomy.—The soft parts of two males and three barren females are at hand. 

A description has been previously given by myself (1911a, p. 117). However, 
it should be added that in one female investigated the branchial opening is open 
in front, but probably torn. In another, a male, it is undoubtedly open; this is 
an old individual, the largest at hand, and here also it may be that it has been in- 
jured during life. In the other three specimens (one male and two females), the 
branchial opening is closed in front. According to Von Ihering (1891, p. 476), 
this opening is closed in 80 pr. et. of the cases. 


ORTMANN: SOUTH AMERICAN NAIADES. 561 


Anal opening closed above; closed part three to four times as long as the open 
part, the latter slit-like, shorter than the branchial, and separated from the latter 
by a solid mantle-connection. Branchial opening with papille, closed in front 
by a firm union of the inner mantle-edges, or, more rarely, open and without this 
connection. Palpi rather large and slightly produced posteriorly, with strongly 
curved lower margins. Their posterior margins are connected for about one- 
third of their length. 

Gills of the usual shape, the inner much wider in front than the outer, its 
anterior end close to the palpi. Inner lamina of inner gill entirely connected 
with abdominal sac. Non-marsupial gills with scattered interlaminar connec- 
tions. Marsupium of the female located in the inner gill, but it does not occupy 
all of this gill, but only a portion in the middle, leaving free a larger part anteriorly, 
and a smaller posteriorly, so that the marsupium appears shifted slightly backwards. 
Interlaminar connections of marsupium arranged in interrupted septa. 


Genus Hyria Lamarck (1819). 
Hyria LaMarcK, 1819, p. 81; Stimpson, 1900, p. 868; 1914, p. 1211. 

This genus is characterized by the alate shape of the shell, possessing wings 
both at the anterior and posterior end of the upper margin. In addition the 
radial beak-sculpture is well developed, covering a considerable part of the shell, 
the posterior ridge is rounded and broad, and the pseudocardinals are much com- 
pressed. The hinge-teeth may be somewhat corrugated, but they do not possess 
distinet vertical ridges. 

The distribution of this genus is restricted to the basin of the Amazon and the 
rivers of Guyana. A key to the species has been furnished by Simpson (1914, p. 
1212), but some of the species may be only forms of others. 


38. HyriaA CoRRUGATA Lamarck (1819). 
Hyria corrugata LaMaARcK and H. transversa Hurt, Stimpson, 1900, pp. 868, 869; 

1914, p. 1212, 1215. 

Type-locality —Unknown. 

Other Localities—Rio Solimoes (= middle Amazon) (Triplodon rugosum Spix, 
Wagner, 1827, p. 35); Rio Yavari, Brazil (southern tributary of Amazon, forming a 
boundary between Brazil and Peru) (Haas, 1916, p. 9, 47). 

New Locality —Sand-bar of Rio Tapajos, Santarem, Parad, Brazil (J. D. Hase- 
man coll., December 6-12, 1909). About fifty specimens, among them two fe- 
males with soft parts. 


562 MEMOIRS OF THE CARNEGIE MUSEUM. 


Several other specimens are preserved in the Carnegie Museum, from the 
Hartman, Smith, and Juny collections, but all are labelled “‘Amazon River.” 

Distribution.—According to Simpson Eastern Peru to Guiana; south through- 
out Brazil. However, the few special localities known are all on the Amazon and 
its tributaries. 

It should be remarked in the first place that all my specimens undoubtedly 
represent but one species, showing a great deal of variation, the various forms all 
connected by intergrades. 


‘ 


Simpson describes this species as having a ‘‘subrhomboidal”’ shape and with 


the beak-sculpture covering only part of the surface. He retains H. transversa 


iad 


Hupé (from Brazil) as a distinct species, which has ‘‘rhomboidal”’ shape, and only 
a “few strong umbonal ridges.”” Specimens from the Rio Tapajos at hand repre- 
sent both forms, and pass gradually into each other, so that I am forced to regard 
H. transversa as only an individual variation of H. corrugata. 

The extreme development of the beak-sculpture, covering the whole shell, 
is found in H. rugosissima Sowerby. Some of my specimens approach this con- 
dition, but none fully agree with Sowerby’s figure (XVII, Hyria, 1869, Pl. 3, fig. 5), 
so that this form is not represented in my material, and I cannot say whether it 
is a good species or not. 

Sowerby (l. ¢., Pl. 2, fig. 3) distinguishes H. exasperata (British Guyana) from 
H. corrugata (Pl. 1, fig. 1), the former being longer and more compressed, the latter 
shorter and more swollen. Simpson unites these two; but among my material I 
have no specimens which corresponds exactly to the corrugata of Sowerby. If the 
two should be different, my specimens would fall under exasperata Sowerby (1869) 
which undoubtedly is synonymous with Triplodon rugosum Spix (1829). 

Frierson (1915, p. 363) has recently described H. amazonia. In outline this 
easily falls within the range of my specimens of corrugata, chiefly specimens with 
less developed beak-sculpture (H. transversa Hupé). But H. amazonia is decidedly 
more swollen. Being founded upon a single speéimen, it is Impossible to decide 
whether amazonia is a good species. 

In shape my specimens vary greatly. They are all rather compressed, but 
there is some variation in this respect. The greatest irregularity, however, is seen 
in the outline and beak-sculpture. The wings of the shell are of various sizes, 
chiefly the posterior one, which may be rather short, or drawn out, broader or 
narrower, and may be more or less elevated. Sometimes the wings assume freakish 
shapes, curving up or down, or being deflected laterally. Thus the whole shel] 
is more or less elongated, and more broadly or more narrowly triangular. The 


ORTMANN: SOUTH AMERICAN NAIADES. 563 


beak-sculpture is generally well developed, and covers all of the shell in young 
specimens; but in older individuals it disappears near the lower margin, and some- 
times it is poorly developed, and present only for a short distance from the beaks 
(form transversa Hupé), but, as stated above, the latter specimens are connected 
with the typical form by intergrades. 

Anatomy—Two females are at hand, one of them gravid, and with eggs (col- 
lected December 10). 

The soft parts have been previously described and figured by myself (191 1a, 
pp. 108; 114, Pl..6, fig: 6, Pl. 7, fig. 6). 

Anal opening closed above; closed part about twice as long as the opening, 
the latter slit-like, separated from the branchial opening by a mantle-connection. 
Branchial opening with small papille, not closed in front. Palpi rather small, 
subtriangular, posterior margins not connected. 

Gills of the usual shape, the inner much wider anteriorly than the outer, its 
anterior end close behind the palpi).2°>. Inner lamina of inner gill entirely conne seted 
with abdominal sac. Non-marsupial gills with scattered interlaminar connections. 
Marsupium of the female in the inner gill, restricted to the middle portion, about 
one-fourth of the gill at anterior end, and a little less than that at the posterior 
end being non-marsupial. Interlaminar connections of marsupium crowded and 
numerous, forming interrupted septa, and assuming in the most central part an 
irregularly quincuncial (reticulate) arrangement. 


Genus Prisopon Schumacher (1817). 
Simpson, 1900, p. 869; 1914, p. 1216. 
Closely allied to Hyria in the doubly alate shell, but differing in the absence 
of beak-sculpture, and the strong development of a sharp posterior ridge. 
A key to the species has been given by Simpson (1914, p. IPAM) 
This genus is also characteristic of Guyana and the Amazon-drainage in Brazil. 


39. PrisopoN ALATUS (Sowerby) (1869). 
Shells: Plate XL, figs. 1, 2, 3. 
Hyria alata Sownrsy, XVII, 1869, PI. 5, fig. 13. 
Prisodon alatus Srupson, 1900, p. 871; 1914, p. 1220. 
Type-locality —Guyana. 


* The shell of this gravid female approaches the form transversa, with the beak-sculpture less 
developed, but with the shape not very elongated. The other female is a normal corrugata, half-grown. 
2% The connection of this gill with the palpi deseribed previously is only accidental, and seen only 


on one side of the larger female; on the other side, and also in the smaller female, the structure is normal. 


564. MEMOIRS OF THE CARNEGIE MUSEUM. 


New Locality.—Sand-bar of Rio Tapajos, Santarem, Para, Brazil (J. D. Hase- 
man coll., December 6-12, 1909). About sixty specimens, all dead shells. 

Distribution.—The discovery of this species, hitherto apparently only known 
from Guyana, in the Amazon-drainage is interesting. 

The shell is easily recognized by the relatively short triangular shape, and the 
excessive development of the anterior and posterior wings. The outline varies a 
good deal, being longer or shorter, and the lower posterior end of the shell may 
be blunt or somewhat pointed. The obesity is also variable. The wings are 
more or less developed, and the posterior one may be longer or shorter, sometimes 
as long as the rest of the shell, narrower or wider, pointed or blunt. It is directed 
straight backwards (forming a straight continuation of the hinge-lie), chiefly so 
in young specimens; but in older ones it may be directed more or less upward, so 
that the hinge-line becomes concave. Upon the posterior slope there are sometimes 
a few (three to five) parallel folds or wrinkles, but most specimens lack these. 

The pseudocardinals (Pl. XL, figs. 2c, d) of this species are very long and com- 
pressed, the posterior of the right valve is longer than the anterior, and extends 
far forwards, so as to be placed in its anterior part below the anterior. In the 
left valve there are also two pseudocardinals, the posterior shorter than the anterior, 
and extending only with its anterior end below the anterior. The upper and inner 
face of the posterior right pseudocardinal in its posterior part, and the space be- 
tween the two teeth in the left valve, has distinet, parallel, and subvertical ridges. 
The lateral teeth (one in right, two in left valve) are only obliquely and granulately 
corrugated, but do not possess parallel vertical ridges. Thus in the structure of 
the pseudocardinals this species differs from other species of the genus (I have been 
able to compare P. castelnaudi, obliquus, brownianus), where these teeth are shorter, 
and the posterior one in each valve is split into several parts, without developing 
vertical ridges. 

My specimens are of all sizes, but none of them reaches that of Sowerby’s 
figure, which measures, from tip to tip of the wings, 115 mm., and from tip of an- 
terior wing to lower posterior end of shell 115 mm. 


MEASUREMENTS. 


Length (Tips of Wings.) So Tleight. |* Diameter. | Figured. 
78 mm. 65 mm. | 40 mm. 25.5 mm. 
ga.“ 69 “« ARS OG Dome | 
op} 7Asy | mil Be [SSPE xa fio wale 


For obvious reasons (odd shape of shell) measurements could not be made here 
in the usual way. It also should be noted that the wings of the largest specimens 


ORTMANN: SOUTH AMERICAN NATADES. 565 


are slightly broken off, and also in the two others they are not quite perfect. The 
length from tip to tip of the wings is most nearly parallel to the hinge-line. The 
height is measured vertically to the hinge-line, from the beaks to the lower margin. 


. 
40. PRIsODON CASTELNAUDI (Hupé) (1857). 
Hyria castelnaudi Hurk, 1857, p. 81, Pl. 16, fig. 1; Sowersy, XVIT, 1869, Pl. 4, 

fig. 8. 

Prisodon castelnaudi Stmpeson, 1900, p. 871; 1914, p. 1220. 
Prisodon obliquus castelnaudi Von InErinG, 1910, p. 135, 137. 

Type-locality—Braail. 

Other Localities —Rio Araguaya, Goyaz, Brazil (Von Ihering); Rio Chingu, 
Para, Brazil (Von Ihering). 

New Locality.—Rio Guaporé, near Rio Sao Simao, Matto Grosso, Brazil 
(J. D. Haseman coll., July 20, 1909). One young male with soft parts. 

In addition, there is in the Carnegie Museum one larger specimen from the 
Hartman collection, labelled “ River Amazon.” 

~ Distribution.—Positively known from the Amazon, two of the tributaries of 
its lower part in Goyaz and Para, and from a tributary of the Madeira in Matto 
Grosso. 

My specimens agree well with the account given by Simpson, but I should say 
that the hinge-teeth are not vertically ridged. The posterior pseudocardinal in 
either valve is cut up by deep fissures into accessory teeth, which are somewhat 
radiating. The lateral teeth are slightly rugose. 

Von Ihering regards this as a variety of P. obliquus Schumacher (= avicularis 
Lamarck), and this is quite possible. 

Anatomy.—A young specimen with soft parts is at hand, probably a male, 
since no marsupial structure can be seen. 

Soft parts like those of Hyria. The palpi are slightly broader, and their 
lower margins more curved. The anterior end of the inner gill is immediately 
behind the palpi. Shape and structure of the gills normal. 


Subfamily Mure.tn (See above, p. 457). 
“General Remarks. 

Shells of various shapes, subelliptical, subovate, subtrapezoidal, or more or 
less rounded. Beak-sculpture absent, only in one case have subconcentric bars 
been observed, which, however, may not be homologous to the real beak-sculpture 
of other Naiades. 


566 MEMOIRS OF THE CARNEGIE MUSEUM. 


Hinge rarely with teeth, which, when present, are much reduced and consist 
only of pseudocardinals or irregular teeth. Real laterals are never present. 

Muscle-scars on inside of shell rather variable. Generally the anterior re- 
tractor-scar is united with the adductor-sear, forming an upper continuation of 
it (thus differing from the normal condition seen in the Hyriine). But in some 
cases the retractor-scar is partially or entirely isolated. Anterior protractor-scar 
quite variable, isolated from adductor-sear or contiguous with it, or even confluent 
with it. The posterior scars are rather uniform, agreeing with the Hyriine, the 
retractor-scar forming an upper process of the adductor-scar. Only in one case 
(Anodontites ensiformis), are these two sears widely separated. Dorsal muscle-sears 
mostly absent; if (rarely) present, only one may be found, or (in Leila) a row of 
them. (In the Hyriine several are always present.) 

The pallial line is mostly simple and parallel to the margin; but in one genus 
(Leila) it forms a shallow sinus posteriorly. This undoubtedly is connected with 
the closing of the branchial opening in front, but unfortunately no soft parts of 
this genus are at hand, so that particulars cannot be given. Very often the pris- 
matic border on the inside of the margin of the shell is unusually wide. 

The ligamental sinus is comparatively large, larger than in the Hyriine; it 
may be broad and deep, but not sharply triangular (heringella), or deep and sharply 
triangular (in the other genera). In Mycetopoda it is shallow, but with a sharp 
lower angle. 

As to the characters of the soft parts see above (p. 457). But it is well to 
point out here that the chief features in which this subfamily differs from the 
Hyrvine are found in the structure of the gills (text-fig. 3, 7, 0, p. 458) which have 
well developed, solid septa, moderately closely set, running parallel to the gill- 
filaments (Pl. XLVIT, figs. 3,4). In the female (Pl. XLVI, figs. 3b, 4b; text-fig. 37, 
p. 458), the septa of the marsupial inner gill are stronger, but not distinctly more 
crowded than in the non-marsupial gills, and have close to the outer lamina (primary 
limb) a ridge on each side, projecting into the lumen of the water canal, incom- 
pletely dividing the latter into two compartments (Pl. XLVIII, figs. 6, 7b, 8). 
The inner compartment, towards the inner lamina, assumes, when charged, the 
function of an ovisac, containing the eggs or embryos (Pl. XLVIII, fig. 7b), which 
do not stick closely together, and this compartment expands to a certain degree, 
the corresponding section of the septa stretching out, while the outer compartment 
(close to the other lamina) retains its shape, and does not contain eggs, thus ap- 
parently serving as a secondary water-tube. 

The size of the eggs is small, 0.07 to 0.09 mm. According to Von Ihering the 


ORTMANN: SOUTH AMERICAN NAIADES. 567 


larval form is a lasidium (Size: 0.10 mm). It is a very singular circumstance 
that I have not been able to find lasidia (or any other form of mature larvee) in 
my material, although a good many gravid females of various species and genera 
are at hand. 


Ture GENERA OF THE SouTH AMERICAN MUTELIN/. 


Mudteline are found in South America and in Africa. Unfortunately, among the 
African forms, the anatomy of Spatha (including the subgenus Aspatharia) is 
alone known (Ortmann, 1910, p. 39; 1918, p. 75); but this genus differs from most 
South American Muteline (Fossula, Monocondylea, Anodontites) by the fact that 
the anal opening is closed above, without forming a supra-anal opening. In the 
South American genera this opening is open and not at all closed, with one exception, 
Mycetopoda, where about the upper half of the anal is closed. In addition, in 
Spatha, the inner gill is free from the abdominal sac, while in the South American 
genera it is connected with it. All other characters are similar. Thus, although 
closely allied to Spatha, the South American genera form a group by themselves, 
and the similarity of Mycetopoda to Spatha in the anal opening apparently indicates 
only parallelism of development, not genetic relationship. 

It is hard to say which group is more primitive, since of the two differing 
characters, the one (anal opening) is more primitive in the American forms, the 
other (inner lamina of inner gill) more primitive in the African Spatha. The 
latter again is rather advanced in the shell, having no hinge-teeth, a condition 
which is also found in most South American Mutelinz, but not in all, for / heringella, 
Fossula, and Monocondylaa have at least pseudocardinals. 

There is no question that among the South American forms, these genera with 
hinge-teeth should be regarded as more primitive. But a confirmation of this 
cannot be found in the anatomy, the latter being alike in all of them. Possibly 
the anatomy of Iheringella might furnish some enlightenment, but of this genus 
the soft parts have never been observed. 

The structure of the hinge might be expected to furnish evidence of the con- 
nection of the Muteline with the Hyriinw. The very fact that there are genera 
among the Muteline with hinge-teeth, indicates that the typical South American 
forms (of the Anodontites-type) are derived from forms with hinge-teeth. But 
the structure of these hinge-teeth is rather peculiar. They are always in a rudi- 
mentary condition, the laterals being missing, and the other teeth corresponding 
to the pseudocardinals cannot be positively homologized with the pseudocardials 
of the Hyriine. Yet we are to assume on account of the many anatomical points 


568 MEMOIRS OF THE CARNEGIE MUSEUM. 


in common with the Hyriine that the Muteline are related to, and probably des- 
cended from, the latter; but connecting links which undoubtedly stand between 
these two subfamilies are as yet unknown, and only the presence among the Muteli- 
ne of forms with hinge-teeth suggests that there once was a closer connection with 
the Hyriine. According to our present knowledge, the two subfamilies are un- 
doubtedly allied; but they are very sharply separated by anatomical as well as 
shell-characters, and it is impossible to form an appropriate idea of their genetic 
connection. 

Simpson (1914, p. 1384 et seg.), in his family Mutelide, admits six South 
American genera: Monocondylewa, Iheringella, Fossula, Leila, Anodontites, and 
Mycetopoda. ‘These are easily distinguished by shell-characters, which are. tabu- 
lated in the following key. 


Key ro THe Sournh AMERICAN GENERA OF MUTELIN&. 
a,. Hinge with more or less developed pseudocardinal teeth. Lunula short or almost absent, not much 
produced in front of the beaks. 
b,. Hinge-plate rather broad, with oblique, compressed or tubercular, alternating pseudocardinals, 
two in each valve, the most anterior-in the left valve...........................Lheringella. 
b». Hinge-plate narrow, with the pseudocardinals stumpy, squarish, or depressed, left valve never ° 
with two distinet pseudoeardinals. 

c,. Left valve with one, right with two stumpy, or squarish, pseudocardinals, which alternate, 
the most anterior one being in the right valve.;...................+.-.......-Mossula: 

c>. Either valve with only one pseudocardinal, which is generally depressed (spoon-shaped), 
that of the left valve being the most anterior.............-.--+-+-++-:=: Monocondylea. 

a». Hinge without any pseudocardina-teeth. Lunula elongated and much produced in front of the 
beaks, forming a kind of anterior ligament. 
b,. Pallial line without a sinus behind. 

c;. Shell rounded, subovate, or subtrapezoidal. Valves closed or somewhat gaping (when the 
shell is elongated, the valves are closed). Anal opening entirely open. Branchial opening 
not closed) mshromts, LOO bMOLMM all yee a ieee eee ae eee Anodontites. 

c». Shell elongated, gaping in front. Anal opening closed above. Branchial opening said to 
be elosed in front (this is doubtful). Foot very long, developed at its distal end into a 
sort of buttons ask ks Cea cee EE ee ace ee M ycetopoda. 

b». Pallial line with a sinus behind. Shell large, subovate, winged. Valves gaping. Branchial 


opening ‘sard ito bevclosed imtiront: +) .6 sce eee oe Oe ee eee Leila. 
gs 


With regard to the genetic connections of these genera, it is clear that we are 
to regard the first three as the more primitive forms, and, judging from the shell, 
Theringella appears to be the most primitive, havmg the most complete hinge. 
There is no doubt that of the others Anodontites is the simplest, but its connection 
with the first three is obscure, since the shell-characters do not connect it more 
closely with any one of them. Both Mycetopoda and Leila seem to have descended 


ORTMANN: SOUTH AMERICAN NAIADES. 569 


from Anodontites, the former being characterized by a specialisation of the foot; 
the latter by a specialisation of the branchial opening. Mycetopoda is also peculiar 
in having the anal opening closed above. We can express this in the following 
diagram: 


Mycetopoda Leila 


Anodontites 
9 


Theringella, Fossula, Monocondylea 


The anatomy furnishes no additional help for the understanding of the phyl- 
ogeny of these genera, except the points mentioned in the key. In fact, the anatomy 
is so disappointingly similar in all of them, that it is practically useless. Only 
in Mycetopoda and Leila have we been able to recognize higher stages of develop- 
ment in the anatomy, but it should be mentioned that I have not been able to 
verify this fact in Leila, of which I have not had the opportunity to examine soft 
parts. The same is true of [heringella. Of Fossula, Monocondylaa, and Ano- 
dontites, I know the anatomy very well, but no differentiations whatever have 
been observed. 

Tue Species of SouTH AMERICAN MUTELIN#. 


Genus IHERINGELLA Pilsbry (1893). 


Pilsbry, 1893, p. 30; Simpson, 1914, p. 1392. 

Characterized by rather broad hinge-plate and compressed or stumpy pseudo- 
cardinals, two in the right and two in the left valve, the anterior pseudocardinal 
of the left valve the most anterior of all hinge-teeth. These teeth, however, are 
rather variable. . 

This genus approaches the Hyriine most closely in its hinge, but in the details 
of its structure it is very different from any of them. It belongs to the La Plata- 
drainage, and possibly also to that of the upper Amazon. 


41. [HERINGELLA BALZANI (Von Ihering) (1893). 


Plagiodon balzani Von Inertia, 1893, p. 69, Pl. 3, fig. 2. 
Theringella balzani Simpson, 1900, p. 914; 1914, p. 1859. 

Type-locality.—Rio Paraguay, near mouth of the Rio Apa, Matto Grosso, 
Brazil. 

New Locality—Rio Paraguay, San Luis de Caceres, Matto Grosso, Brazil 
(J. D. Haseman coll., May 25, 1909). Two complete shells and one left valve. 


570 MEMOIRS OF THE CARNEGIE MUSEUM. 


Distribution.—Ixnown only from the upper Rio Paraguay. Simpson also 
gives “San Paulo, Brazil,” but I do not know upon what authority. 

My specimens agree well with Von Ihering’s description and figure, but they 
are larger. Von Ihering says that the color of the epidermis is dark olive or black- 
ish. In our largest and smallest (half-shell) specimens the surface is much corroded 
and worn, and brownish green. In the specimen of medium size, which is better 
preserved, it is yellowish green, with a few scattered dark green spots upon the disk, 
becoming more frequent near the beaks. Upon the posterior ridge, there are a 
few fine, interrupted, dark green rays, and a broader ray runs over the posterior 
slope. 

In the two smaller specimens, the structure of the hinge corresponds entirely 
with Von Ihering’s description. In the largest, however, the anterior tooth of 
the left valve is obsolete, and so is the groove between the two teeth. The pos- 
terior tooth is broad and slightly bifid. In consequence of this the groove of the 
right valve is also broader and has a radial ridge in its bottom, and the anterior 
tooth of the right valve is very small. I consider this an abnormality. In this 
specimen there apparently is only one (bifid) tooth in the left valve, and two small 
ones in the right, with an accessory ridge in the groove between them. 

In all three of my specimens, the ligamental sinus is wider and shallower than 
figured by Von Ihering, which may be due to their greater age. 


MBASUREMENTS. 


Length. | Height. 


Diameter. Beaks. 


34mm. | 26mm.=76 pr. ct. of L. | 16 mm.=47 pr. ct. of L. ct. of L. 

40 ol * =78 ne Zit —= 53 p oe 

AG as 30 “ =76 nS 23," =50 2 

st 20 oo = 84 a li) So Soe “ “(Von Ihering, 


_ beaks from figure) 


The measurements given by Simpson (1914, p. 1395) are entirely wrong, and 
are those of Fossula balzani Von Ihering. 


Genus Fossuuta Lea (1870). 
Lea, Syn. 1870, p. 72; foot-note 1; Von Ihering, 1893, p. 62; Simpson, 1900, p. 914; 

1914, p. 1396. 

The distinguishing character of this genus is found in the hinge-teeth, of which 
there are two in the right valve, enclosing between them one in the left valve. The 
hinge-plate is narrow, the teeth are stumpy (not vertically compressed or spoon-like 
as in Monocondylea). There are traces of additional teeth and irregularities of 
the hinge, which, however, are variable. The “cement processes” described by 
Von Ihering are not always present. 


-—— 


ORTMANN: SOUTH AMERICAN NAIADES. 571 


A key to the three known species has been given by Von Ihering (1910, p. 115). 
Two of the species are from the Parand-drainage, and one is from a coastal river 
in eastern Brazil, the Rio Paraguassti in Bahia. 


42. FossuLA FOSSICULIFERA (D’Orbigny) (1835). 
Section of gills: Plate XLVIUII, fig. 6. 

Monocondylea fossiculifera D’OrBiany, 1848, p. 614, PI. 80, figs. 5—7. 

Unio fossiculiferus SowErsy, XVI, 1868, Pl. 96, fig. 521. 

Fossula fossiculifera VON InERING, 1893, p. 64, Pl. 3, fig. 2; NEHRING, 1893, p. 164; 
Simpson, 1900, p. 914; Von Inertna, 1910, p. 115; Simpson, 1914, p. 1396. 
Type-locality Rio Parana, Iribucua, above Corrientes, Argentina. 

Other Localities.—-Rio Parani and lower Rio Tieté, Sao Paulo, Brazil (Von 

Thering); Rio Piracicaba, Piracicaba, Sao Paulo, Brazil (Von Ihering) (Nehring). 
Localities Represented in the Carnegie Museum.—Rio Piracicaba, Piracicaba, 

Sao Paulo, Brazil (Von Ihering donor). One specimen. Rio Tieté, Salto de 

Avanhandava, Sao Paulo, Brazil (J. D. Haseman coll., September 15, 1908). One 

specimen. Rio Tieté, Salto das Cruzes, Sao Paulo, Brazil (J. D. Haseman coll., 

September 22, 1908). One female with soft parts. Rio Tieté, Itapura, Sao 

Paulo, Brazil (J. D. Haseman coll., September 28, 1908). One female with soft 

parts. 

Distribution —Rio Parana and its tributaries from Argentina to Sao Paulo, 

Brazil. ; 

This species has been well figured by D’Orbigny and Von Ihering, and has 
been well described by the latter. No further details need to be supplied. 


MEASUREMENTS. 


Sex Length. | Height. | Diameter Beaks 


Salto das Cruzes.......-| 2 | 56mm. | 44 mm. =78 pr. ct. of L. | 27 mm. =48 pr. ct. of L. | at 21 mm. =38 pr. ct. of L. 
PAD UR pe ee reeks rarh nicl ear [IOS Yas Coen oo : 38 “ =651 ss 23 “ =31 * 
Avanhandava.......... es 2 5 “ 138 “ =48 25 “ =32 
Piracicaba........ Em (ee 64 esi io [39 ‘ =49 - DL Sess 

(Von Ihering)......... he hes Gone = s)) Bist open ty ~ Wt es Say? 


According to Von Ihering the height varies from 80 to 89 pr. ct., while in D’Or- 
bigny’s specimen it is 77 pr. ct. 

Anatomy.—Partially described by Von Thering (1893, p. 69) for the male. I 
am able to supplement this from two barren females at hand. 

Anal opening entirely open, very large, with smooth inner edge, very faintly 
crenulated in the lower part, separated by a solid mantle-connection from the 


ie MEMOIRS OF THE CARNEGIE MUSEUM. 


branchial opening, which has small papillae on the inner edge. These papille 
extend rather far forward, decreasing in size, and disappearing gradually. Palpi 
moderately large and broad, semicircular, posteriorly with a short truncation 
forming the posterior margins, which are not connected. 

Gills rather wide, the inner the wider, chiefly anteriorly, its anterior end 
immediately behind the palpi; that of the outer gill at the highest point of the 
attachment-line of the mantle, so that the lower margin of the outer gill is curved, 
the gill narrowing considerably in front, while the inner is not much narrower in 
front, and has the lower margin rather straight. Inner lamina of inner gill entirely 
connected with abdominal sac. Both gills with well developed, strong septa. The 
non-marsupial outer gill has the septa alternately stronger and thinner, but the 
alternation is irregular. The marswpiwm is in the inner gill of the female. Here 
the septa are more uniform and very strong, but hardly more closely set than in 
the non-marsupial gill. Where the septa are inserted at the outer limb, they have 
a swelling on each side, which forms a vertical ridge projecting into the lumen of 
the water-tubes (See Pl. XLVIII, fig. 6). This ridge is less developed in my younger 
female, yet perfectly distinct. The septa near the anterior and posterior end of 
the inner gill do not have marsupial structure, but the marsupial part is very large, 
_ occupying nearly the whole gill. 


Genus MonoconpyLma D’Orbigny (1835). 
D’Orbigny, 1835, p. 37; 1848, p. 611; Simpson, 1900, p. 910; 1914, p, 1384. 

Normally each valve has only one pseudocardinal tooth, that of the left valve 
being more anterior. The teeth are more or less depressed (spoon-shaped). Traces 
of additional teeth may be present, but they are insignificant and variable. 

A key for the species has been given by Simpson (1914, p. 1385), which, how- 
ever, is artificial and unsatisfactory, and the essential characters apparently have 
been misunderstood. Moreover, I believe that M. guarayana D’Orbigny (1843, 
Pl. 68, figs. 4-7) does not belong here, but probably to [heringella. 

The specimens before me all have a cloth-like epidermis, with crowded, ir- 
regular and anastomosing, concentric lines, which are lamellarly elevated. But 
very often these fine lamellz are abraded, so that the surface appears smooth. 
Nevertheless the lamellze are generally preserved in some part of the shell, chiefly 
on the posterior slope and near the margins, and, even when abraded, they can be 
easily noticed as fine lines. The species at hand, which have been treated by Simp- 
son have been called “smooth or lightly concentrically striate.”’ He distinguishes 
them according to the outline, orbicular, obovate, elliptical, subrhomboidal, or 
subquadrate, but it is extremely hard to draw a line between these terms. 


ORTMANN: SOUTH AMERICAN NAIADES. 573 


The following key is intended only for the distinction of the forms at hand. 


Key to THE Specips oF MOoNoconpdyL@aA. 
a. Shell small, or of medium size (at the utmost 50 to 60 mm. long). Lamellar striz of epidermis well 
developed, but sometimes abraded. Color of epidermis greenish black or brown. 
by. Shell more or less oblique, subtrapezoidal, or angularly suborbicular, with a well developed 
posterior upper angle, high behind, narrower in front. Color of epidermis greenish black. 
Prismatic zone on inside of margin of unequal width, very wide along anterior portion of 
lower margin. 
c;. Shell angularly suborbicular, rather high and short, height about 80 pr. ct. of length. Sides 
of disk not flattened. 
d,."Shell compressed, diameter 50 pr. ct. or less of length. Beaks not much elevated. 
M. lentiformis. 
dy. Shell more swollen, diameter 58 to 59 pr. ct. of length. Beaks more inflated and 
GIERDIRRGICS =, = tdtgh aba Cees ee Nee ies ee oe 2 PE Se! M. paraguayana. 
c». Shell subtrapezoidal, more elongated, height about 70 pr. ct. of length. Sides of disk more 
or less flattened. 
d,. Shell more swollen, beaks more prominent, hinge-line rather strongly ineurved under 
i eCHDeaKcee rR eae Se Coe hs ae eemens RO Os tl cles outer oea reel M. minwana. 
d». Shell less swollen, beaks less prominent, hinge-line less incurved under the beaks. 
M. mtnuana parchappt. 
b». Shell very little, or not at all oblique, subovate or subelliptical in outline, with the posterior 
upper angle rounded and poorly developed. Obesity of shell very great, and beaks much 
swollen and inflated. Color of epidermis brown. Prismatic zone on inside of margin narrow 
cial GH MeGihy Tiare \\ 210 hd Nae Bios Ei opeckuteediiacus pimesS oops Sood on oc cbc oc! VW. obesa. 
a». Shell large (about 100 mm. long). Lamellar strie of epidermis poorly developed upon the disk, 
distinct only near the margins. Color of epidermis from yellowish olive upon the disk and toward 


Chesbeaksatondarkslbrowm toward the amareinss.... say. 22-1 o-oo ae eens oie tee M. hollandi. 


The species of this genus cover a rather large range in South America being 
found all over the La Plata-drainage, in the Amazon-drainage in Bolivia and 
Brazil, in the Rio San Francisco in eastern Brazil, and also in coastal streams in 
southern Brazil (Rio Grande do Sul). 


43. MonocoNDYL@A LENTIFORMIS Lea (1866). 
Anatomy of gills: Plate XLVI, fig. 3. 

Monocondylea lentiformis Lea, Obs., XII, 1869, Pl. 36, fig. 86; Pirspry & Rusa, 
1896, p. 81; Smupson, 1900, p. 912; 1914, p. 1392; Corsi, 1901, p. 452; Haas; 
1916, pp. 25, 54. 

Aplodon lentiformis Von IteriNG, 1893, p. 67; NEHRING, 1893, p. 164. 
Type-locality.—South America. 
Other Localities—Rio Piracicaba, Piracicaba, Sao Paulo, Brazil (Von Ihering) 

(Nehring); Rio Uruguay, Salto Oriental, Uruguay (Haas); Rio de la Plata, Colonia, 

Uruguay (Pilsbry & Rush). 


574 MEMOIRS OF THE CARNEGIE MUSEUM. 


New Localities —Rio Uruguay (in mud), Uruguayana, Rio Grande do Sul, 
Brazil (J. D. Haseman coll., February 5, 1909). Four specimens with soft parts, 
males and females. Rio Cacequy, Cacequy, Rio Grande do Sul, Brazil (tributary 
to Rio Ibicuhy, to Uruguay) (J. D. Haseman coll., February 2, 1909). Two speci- 
mens with soft parts, male and female. Rio Jacuhy, Cachoeira, Rio Grande do 
Sul, Brazil (tributary to Rio Guahyba) (J. D. Haseman coll., January 26, 1909). 
Two specimens. 

Distribution.—Known from the Rio de la Plata, and up the Uruguay, and from 
the upper Parand drainage in SAo Paulo. The species has not been found in the 
lower and middle Parand, although it should be expected there. In addition it is 
found, as our specimens show, in the drainage of a coastal stream in Rio Grande do 
Sul (Guahyba). This is a remarkable fact, but it should be borne in mind that the 
head-waters of the Ibicuhy (Uruguay drainage) and those of the J acuhy (Guahyba- 
drainage) closely interlock, and that stream piracy in this region is quite probable. 

Characters of the Shell.—Shell rather small (maximum length 44 mm.), moder- 
ately thick, outline more or less subeircular or subpolygonal. Height 77 to 88 pr. 
ct. of length. - Valves very little gaping in front, sometimes almost closed. Dorsal 
margin straight behind the beaks, or gently convex, much lower in front of the 
beaks, and straight here or even somewhat concave, passing in a curve or a very 
blunt angle into the anterior margin. Posteriorly the dorsal margin passes in 
a distinct, or indistinct, blunt angle into the posterior margin. The latter descends 
obliquely, and is straight, rarely slightly convex or coneave. It passes in a curve 
into the posterior part of the lower margin, forming the blunt posterior end of the 
shell. The lower margin is curved, the strongest part of the curve and the lowest 
point of the shell is situated at 54 to 60 pr. et. of the length from anterior end, and 
is thus immediately behind the middle. From this point the lower margin curves 
up rather strongly in the posterior part. In the anterior portion it is very gently 
curved, or almost straight, and finally curves up sharply into the anterior margin. 
Thus the anterior end of the shell appears narrower than the posterior, and the 
shell has the shape of an irregular pentagon. 

Valves very gently convex, rather compressed, greatest convexity behind the 
middle of the shell, without a distinet posterior ridge. Sides not flattened. Toward 
the anterior and posterior end the shell is somewhat compressed. Diameter 41 
to 51 pr. et. of the length. Beaks little swollen, and very little prominent, located 
at 31 to 39 pr. ct. of the length. Lunula narrow and short. 

Epidermis dull, not shining, with very crowded, irregular concentric lines, 
which form fine lamelle, and give a cloth-like appearance to the surface. But 


ORTMANN: SOUTH AMERICAN NAIADES. 575 


these lamellae may be worn off in part, and the surface may be smoother. No 
distinct radial sculpture is visible, but there may be a trace of a radial rib upon the 
posterior slope. Color of epidermis blackish green, without color-markings, ex- 
cept traces of one or two dark rays upon the posterior slope. 

Hinge-line straight behind the beaks. In front it is curved down more or 

less suddenly, and carries a single pseudocardinal tooth in each valve. The tooth 
of the left valve stands in front of, and somewhat below, that of the right valve. 
Both teeth are vertically depressed, somewhat spoon-shaped, and project under 
the edge of the opposing valves into corresponding shallow grooves. Ligamental 
sinus triangular, not deeper than wide; its anterior margin more or less oblique to 
the hinge-line. 
; Nacre very iridescent, whitish, but generally with salmon, pink, or pale purple 
stains, chiefly in the cavity of the shell. Irregular radiating lines present, but 
only near the margin. Nacreless (prismatic) zone of irregular width, narrow be- 
hind, suddenly increasing in width at the lower point of the lower margin, and re- 
maining wide to near the anterior margin. Greatest width of this zone over half 
the distance of mantle-line from margin. Color of nacreless zone dull olive, gray- 
ish, or grayish red. 

Cavity of shell and beaks shallow. Anterior adductor-sear well marked, ovate. 
Anterior retractor-scar small, but distinet, separated from or connected with the 
adductor-sear, lying in the left valve on the base of the pseudoecardinal tooth. An- 
terior protractor-secar connected with adductor-sear. Posterior adductor-sear 
faint, ovate; posterior retractor-scar forming a triangular upper projection of 
adductor-sear. No dorsal sears. Pallial line subconcentric to the margin. 


MEASUREMENTS. 


Localities. | No.|Sex. Length. | Height. | Diameter. | Beaks. yreatest Height. 
Cachoeira... 1 | ? 34mm. 27 mm. =79% of L.|14 mm. =41% of L.| atl1 mm.=32% of L.| at 20.5 mm. =60% of L. 
Uruguayana .| 1 | /388 “ |31.5 “ =83 “ 18 oe AONE | 15 =39 4 | 22 asi . 
Cacequy....| 2} (39 ‘ |30 eee ye 16 ~ .=41 | 13 an —-rs | 23 Oo 

Don. TOUS ste eer 6 ig Gg A as CTT SB 237 NES 3=59 
Uruguayana .| 3 | 9 |39 “ (34.5 “ =88 1192530 — FO ae | 14 = SON 21 - 

Do. Deltas. selodcDle Gly —-- 18 “ =44 “* | 13 Say 24 
Do. AS ROU a2 « § 36 Oe 20.5 “ =49 “ 15 =36 23 
Cachoeira...| 3.| ? [43 ‘ |34 9) 19 i = 44 13.5 =31 29 


Remarks.—These measurements agree well with those given by Von Ihering 
and Nehring. According to Von Ihering the height ranges from 80 to 84 pr. et. of 
length, the diameter from 46 to 51 pr. et., while Nehring gives for the height 77 to 82 
pr. et., the diameter 46 to 49 pr. ct. Lea’s original figure shows, according to 
Von Ihering, 80 pr. et. for the height, and 44 pr. ct. for the diameter. The speci- 


576 MEMOIRS OF THE CARNEGIE MUSEUM. 


mens from Cachoeira (Guahyba-drainage) entirely correspond with the others 
in these respects, and I cannot distinguish them by any other characters. 

The chief features of this species are the subcircular, or rather rounded-pen- 
tagonal outline, the great height of the shell, the location of the greatest height 
close behind the middle of the shell, and the flatness of the valves. If properly 
placed, with the ligament horizontal, it is seen that the shell is distinetly oblique, 
and that the anterior end is narrower. 

Anatomy.—Three males and three barren females are at hand. 

Von Ihering (1893, p. 69) has mentioned a number of anatomical characters, 
but his account is not complete. 

‘Anal opening entirely open, large, its inner edge with distinet crenulations 
in the lower part, otherwise smooth, separated from the branchial opening by 
a mantle-connection. Inner edge of branchial opening with distinct, but small, 
papille. Palpi moderately large, semicircular, briefly truncated behind, the pos- 
terior margins not connected. 

Gills (Pl. XLVI, figs. 3a, b) of medium width, the inner the wider, chiefly in 
front; the outer narrowing anteriorly, its anterior end near the highest point of 
the mantle-attachment-line. The inner gill very little narrowed in front, beginning 
immediately behind the palpi. Inner lamina of inner gill entirely connected with 
abdominal sac. 

Gills with well developed septa. Those of the male (Pl. XLVII, fig. 8a) and 
of the outer gill of the female alternately stronger and weaker. This alternation, 
however, is not very distinct, and is chiefly seen in the middle of the gill. In 
the female (Pl. XLVII, fig. 3b) the inner gill is marsupial, with the septa more 
uniform and stronger, but hardly more crowded. At the point of union with the 
outer lamina, the usual swelling is present, indicating the ridges projecting into 
the water tubes. The most anterior and most posterior extremity of this gill 
has not the marsupial structure, but the marsupium occupies nearly the whole 
gill. 

In the specimen sectioned, the swellings of the septa are located nearly in 
the middle. However, the part of the septa from the swelling toward the inner 
lamina is thicker, and has more strongly developed epithelium, indicating that 
this is the part which stretches out, when gravid. The condition seen in this 
specimen undoubtedly is due in part to its barren character, in part to the state 


of preservation. 


i i 


ORTMANN: SOUTH AMERICAN NAIADES. 5 


~J 
~I 


44, MoONOCONDYLMA PARAGUAYANA I)’Orbigny (1835). 


Monocondylea paraguayana D’OrBIGNY, 1843, p. 612, Pl. 70, figs. 5-7; Stimpson, 

1900, p. 911 (in part); 1914, p. 1387. 

Unio paraguayana SowErsy, XVI, 1866, Pl. 52, fig. 273. 

Type-locality.—Rio Parana, Itaty, near Corrientes, Argentina. 

Other Locality —Rio Batel, Province Corrientes, Argentina. 

New Locality—Rio Uruguay (in mud), Uruguayana, Rio Grande do Sul, 
Brazil (J. D. Haseman coll., February 5, 1909). One female with soft parts. 

Distribution Known from Rio Parana and its tributary, the Rio Batel in 
Argentina, and from the Rio Uruguay. 

Characters of Shell—Shell moderately thick, and of medium size (maximum 
length 59 mm.). Outline briefly subtrapezoidal, rather high (height 77 to 81 pr. et. 
of length), distinctly oblique, but approaching an angularly suborbicular shape. 
Valves in front gaping very little. Dorsal margin behind the beaks slightly convex, 
much lower in front of the beaks, where it is distinctly concave, and passes into the 
anterior margin in a blunt, but distinct, angle. Posteriorly the dorsal margin passes 
into the posterior margin in arather sharp curve, forming a blunt angle. Posterior 
margin descending obliquely, but very steeply, almost straight, and curving into the 
lower margin, forming with it the broadly rounded posterior end of the shell. 
Lower margin very little curved in the anterior part and sloping upward; posteriorly 
more distinctly curved. Its lowest point (and the greatest height of the shell) at 
about 57 pr. ct. of the shell (60 pr. ct. according to D’Orbigny’s figure). In front, 
the lower margin curves up into the anterior margin. The anterior end of the 
shell is narrower than the posterior, thus producing the oblique shape. 

Valves very convex, chiefly so in the anterior part and backward to the pos- 
terior ridge, and without any flattening upon the sides. Behind the posterior 
ridge the shell is strongly compressed, so that the posterior slope and the upper 
posterior angle appear almost alate. The most extreme anterior end of the shell 
is also slightly compressed. Diameter 59 pr. ct. of the length (58 pr. ct. according 
to D’Orbigny). Beaks inflated and swollen, incurved, projecting over the lunula, 
but only slightly elevated above the posterior part of the upper margin. Lunula 
distinet, short, triangular, about half as wide as long. 

Epidermis dull, with crowded, irregular, concentric lines, which frequently 
become lamellar: probably, where not lamellar, they are worn off, and originally 
the whole epidermis was cloth-like. No radial sculpture visible. A radial rib 
upon the posterior slope, but rather indistinct (much less distinet than in D’Or- 


578 MEMOIRS OF THE CARNEGIE MUSEUM. 


bigny’s figure, and hardly forming a point and an emargination on the posterior 
margin, as in this figure). Color of epidermis dark grayish green to blackish, the 
grayish green shade due to the preservation of the lamellae. A rather distinct 
black radial ray upon the rib of the posterior slope, and faint traces of additional 
rays in front of and behind it. 

Hinge gently curved behind the beaks. Under the beaks it is sharply curved 
down, and in front of them it curves up again, thus becoming concave. Each 
valve has a single pseudocardinal tooth of the typical shape; that of the left valve 
anterior to, and a little below, that of the right; both triangular and depressed, 
and projecting under the margin of the opposite valve, where they fit into shallow 
grooves. Ligamental sinus triangular, wider than deep, its anterior margin oblique 
to the hinge-line. 

Nacre very iridescent, whitish, with a faint salmon blush in the cavity of 
the shell, and purple and greenish reflections toward the margins. Irregular 
radiating lines are present toward the margin. Prismatic zone of unequal width, 
rather narrow behind, widening quite suddenly at the lowest point of the shell, 
and remaining wide along the anterior ascending part of the lower margin, narrowing 
again at the anterior end. Color of prismatic zone grayish green. 

Cavity of shell and beaks moderate. Anterior adductor-sear deep, elliptical. 
Anterior retractor-scar small, at the upper end of the adductor-sear, distinetly 
isolated in left valve, narrowly connected with it in the right. Anterior protractor- 
sear small and united with adductor-sear. Posterior adductor-sear faint, subovate, 
with an upper triangular projection formed by the posterior retractor-scar. No 
dorsal sears. Pallial line subeoncentric to the margin. 


MEASUREMENTS. 


l : Te : ; 
Sex. | Length. Height. Diameter. 


Beaks. | Greatest Height. 


2 | 53 mm. 43 mm. =S81 pr. ct. of L. 31 mm. =S9 pr. ct. of L.| at 16 mm. =30 pr. ct. of L. | at 30 mm. =57 pr. ct. of L. 


Remarks.—In general outline this species is much like M. lentiformis, as is 
shown by the proportion of height to length and the location of the greatest height 
of the shell. It markedly differs, however, in the much more swollen shell (diameter 
59 pr. et. as against 41 to 51 pr. et. in lentiformis), and the more inflated beaks. 
In consequence of the very convex disk, the posterior slope appears much more 
compressed and alate. 

Anatomy.—The specimen at hand for examination is a barren female. 

The structure is absolutely identical with that of M. lentiformis, and nothing 
is to be added, except that the crenulations of the lower part of the anal opening 


SMITHSONIAN INSTITUTION 
UNITED STATES NATIONAL MUSEUM 


WASHINGTON, D.C. 
June 2, 1931. 


Dr. F. Haas, 

Senckenberg Museum, 
Victoria-Allee 7, 

Frankfurt am Main, Germany. 


Dear Doctor Haas: 


Your fine letter of May 20 reached me last week, and the sepa- 
rates and photographs promised me came yesterday. 


I think you have made some very serious errors in your treatment 
of the South American Naiads. Your preliminary discussion of the genus 
Anodontites is unfortunate in thet it shows thet you, like everybody else 
I think, with the exception of myself, do not understand the real type of 
the genus, namely, crispatus Bruguiére. Ortmann's identification of 
crispatus was erroneous; the shell he handled was Anodontites colombiensis 
Marshall; consequently the subgenus Styganodon Martens must stand. 1 think 
it is one of the best of the subgenera or sections of Anodontites. Simpson, 
unfortunately, included in his synonomy of crispatus, uberulus Gould and 
reticulatus Sowerby. but you have made matters worse by including napoensis 
Lea. All four of these are absolutely distinct species, and napoensis does 
not belong even in the same subgenus as crispatus, but in a new subgenus 
which I have gust described, of which the type will be colombiensis Marshall. 
The National Museum is about to publish a paper which I heve prepared, giv- 
ing detailed information, with excellent photographs, of the whole history 
of Anodontites crispatus as type of the genus. 


Under soleniformis of Orb., nehringi and colombiensis surely are 
in the wrong place. We have authentic specimens of soleniformis and of 
nehringi, and the type of colombiensis; in fact soleniformis is so dis- 
tantly related to the other two species that it really should go in a sepa- 
rate subgenus. In other words, these three species belong in three different 
Subgenera or sections. 

Upon your return from Africa we may discuss some of the other parts 
of your paper or I may have prepared a review of it. Just now Il am ina 
hurry to write to you in the hope that my letter will reach you before you 
start for Africa, because I want to urge upon you to collect, if possible, 
some Mutelid in a gravid condition. The great need at the present time in 
the study of the family Mutelidae is confirmation or denial of Ihering's 
statement that they have what he calls a lasidium instead of a glochidiun. 

I have made strenuous efforts to obtain ripe embryos from some South Ameri- 
can species, but thus fir have been unable to'do so. I feel sure that 
Ihering made a mistake, but until we prove him mistaken we must accept his 
statement, because he is a naturalist of no mean standing, and it would not 
do for us to say that there is no lasidium simply because we think such is 
the case, while he claims to have actually observed them. 


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Dr. F. Haas-2. 


Your request for photographs of Unio emarginatus Lea will receive 
early attention, and the photographs will probably be in Frankfurt upon 
your return from Africa. 


Congratulations upon your opportunity to make these explorations in 


_ Africa, and with kind regards, 1 remain, 


Very truly yours, 


William B. Marshall 
Assistant Curator, 
Division of Mollusks. 


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ORTMANN: SOUTH AMERICAN NAIADES. 579 


are less distinct, and that the palpi appear a little larger, with longer posterior 
margins, which are connected at the base. These differences, however, may be 
due to preservation. 

The septa of the inner marsupial gill also have the characteristic swelling, 
not so close to their insertion with the outer lamina, but more toward the middle 
of the septum. 


45. MonoconDYL@&A MINUANA D’Orbigny (1835). 
Section of gills: Plate XLVITI, fig. 7. 

Monocondylea minuana D’OrsIGNy, 1848, p. 612, Pl. 70, figs. 8-10; Corst, 1901, 

p. 452, fig. 34; Simpson, 1914, p. 1588. 
Unio minuanus SowErBy, XVI, 1868, Pl. 91, fig. 497. - 
Monocondylea pazii Lea, Obs., XII, 1869, Pl. 36, fig. 88; Pirspry & Rusu, 1896, 

p. 81. 
Monocondylewa paraguayana Stupson, 1900, p. 911 (pro parte). 


Type-locality—Canelon Grande and del Rosario, Banda Oriental, Uruguay 
(Arroyo Grande flows North to Rio Negro; Arroyo Rosario flows South to Rio de la 
Plata). 

Other Localities. 
Colonia, Uruguay (Pilsbry & Rush, pazi7). 


Arroyo de las Vacas, Uruguay (Corsi); Rio de la Plata, 


New Localities —Rio Uruguay, (in mud) Uruguayana, Rio Grande do Sul, 


Brazil (J. D. Haseman coll., February 5, 1909). Five specimens with soft parts, 
males and females. Rio Jacuhy, Cachoeira, Rio Grande do Sul, Brazil (J. D. 
Haseman coll., January 26, 1909). Five specimens with soft parts, males and 
females. 

Distribution.—Rio de la Plata and its tributaries in the Banda Oriental; Rio 
Uruguay and Rio Negro drainages; and in Guahyba drainage in Rio Grande do Sul. 

Characters of the Shell.—Shell moderately thick, rather small (maximum length 
55 mm.). Outline subtrapezoidal, strongly oblique, rather elongated (height 67 
to 72 pr. et. of length). Valves very slightly eaping at anterior end. Dorsal 
margin straight behind the beaks, or gently convex, much lower in front of beaks, 
where it may be straight or somewhat concave, forming with the anterior margin a 
more or less distinct, obtuse angle. Posteriorly the dorsal margin passes into the 
posterior margin in a more or less distinctly obtuse angle. Posterior margin ob- 
liquely descending, straight, or gently curved, passing into the lower margin in 
a strong curve, which forms the rounded lower posterior end of the shell, not 
much elevated above the base-line. Lower margin in its middle and anterior part 


580 MEMOIRS OF THE CARNEGIE MUSEUM. 


very gently curved or almost straight, sloping upward; the lowest point located 
rather far backward (at 66 to 77 pr. et. of the length). Anteriorly and posteriorly 
the lower margin curves up into the anterior and posterior margins. Anterior 
end of shell markedly narrower than the posterior. 

Valves very convex, but distinctly flattened upon the sides of the disk, which 
flattening may even become a shallow depression. Greatest convexity in front 
and behind the flat area, and the posterior convexity, forming the rounded pos- 
terior ridge, is the stronger. Posterior slope somewhat compressed and elevated, 
but hardly alate. At its anterior end the shell is also a little compressed. Diameter 
50 to 56 pr. et. of length, but sometimes falling below 50 pr. et., and such specimens 
approach the var. parchappi. Beaks more or less swollen, inflated, and incurved, 
prominent over the lunula, but only little elevated above the posterior part of 
the upper margin.. Lunula distinct, short, elongated triangular, variable, narrower 
in young, broader in old specimens, where it may be half as wide as long. 

Epidermis dull, cloth-like. Fine and crowded, anastomosing, concentric 
striz are elevated as fine lamella, but often they are abraded. No radial sculpture 
visible, and there is hardly a trace of a radial ridge upon the posterior slope. Color 
of epidermis dark grayish green, without any trace of color-markings, except oc- 
casionally a mere indication of a dark ray upon the posterior slope. 

Hinge straight, or gently curved, in its posterior part. Under the beaks it 
curves down more or less suddenly, and then becomes straight again, or even some- 
what concave. The curvature of the hinge-line is quite variable, and corresponds 
to the varying degree of the development of the beaks. Pseudocardinal teeth 
as in M. paraguayana. Ligamental sinus triangular, wider than deep, with its 
anterior margin oblique to the hinge-line. 

Nacre very iridescent, whitish, with greenish and purplish tints, chiefly pos- 
teriorly. Irregular radiating lines present, but faint in old specimens.  Pris- 
matic zone of unequal width, rather narrow behind, suddently widening at the 
lower point of the lower margin, and remaining wide to near the anterior margin. 
However this widening is not so strongly pronounced as in M. paraguayana, and 
is also individually variable. Color of prismatic zone greenish gray. 

Cavity of shell and beaks moderate. Anterior adductor-sear sharply and 
rather deeply impressed, subelliptical; anterior retractor-scar small, connected with, 
or separated from, adductor-sear; anterior protractor-sear connected with adductor- 
sear. Posterior adductor-sear distinct, but less strongly impressed; sear of the 
posterior retractor forming a short, triangular upper process of it, which, in a few 
specimens, is partly separated from it. No dorsal sears. Pallial line distinct, 
subconcentric to the margin. 


ORTMANN: SOUTH AMERICAN NATADES. 581 


MEASUREMENTS. 


Localities. No.Sex.| Length. 


Height. Diameter. Beaks. | Greatest Height. 
Uruguay- | | | 
ana....-| 1 |o|24 mm.|17 mm.=71% of L.|12 mm.=50% of L.| at 9 mm. =38% of L.| at 18.5 mm. =77° i Of L. 
Do. 3 | 2 |35 5 20 ill a oe ee DO eee 12 aoe ve | 25 ik 2 
Do. 6 | 92 |39 “ \28 TPN er (74 oe 22 =56 te 14 =36 oy | 27 =69 
Do. 5 | ot |41 28 =68 21 =51 Be 14 =34 27 =66 
Do. .-| 7 | |48 33 =69 24 =I) ty 4 | 33 =69 
Cachoeira..| 1 | o |28 19.5 =70 12:5) =45 9.5 =34 18.5 =66 
Do. 2 | 9 134.5 23 =67 16.5 =48 11 =3y. 23 =67 
Do. x | ? |36 27 =e: 16.5 =46 11 =31 | 25 =69 
Do. 3/9 \43 30 =70 22 — pl 3 =30 | 29 =67 
Do. 419 |44 30.5 =69 21.5 =49 12 =27 } 29 =66 


Remarks.—The measurements for minuana given by D’Orbigny in the text and 
those taken from his figures do not agree, but according to the latter the height 
is about 64 to 67 pr. et. of length, and the diameter about 50 pr. ct. Our specimens 
from Cachocira have, on the average, a smaller diameter (falling as low as 45 pr. 
ct.), and in this respect they are transitional toward the variety parchapp7; but in 
other characters (beaks and hinge-line) they agree better with typical minuana. 

M. pazi Lea is apparently the same species. Simpson unites it with parchappi, 
and it indeed approaches the latter in obesity, having a diameter of 46 pr. ct., 
(parchappi of D’Orbigny has 43 pr. ct.), but here again the beaks and the curvature 
of the hinge-line are more like minuwana, and for this reason I place it here. 

Just because such intergrades do exist, I regard parchappi as a variety of 
minuana (See below). Where the line between the two forms should be drawn re- 
mains doubtful, and naturally it could not be expected that there is a sharp line. I 
have named as miuana my specimens with the diameter of 45 pr. ct. and over, 
because their beaks and hinge-line are more like those of minuana, but this procedure 
possibly may require modification, when more material is studied. 

Anatomy.—I have examined the soft parts of six males, and of five females. 
Two of the latter, collected February 5 (Uruguayana), were gravid. 

Lea (Obs. XII, 1869, p. 273) has described the soft parts of M. pazi, and, as 
far as it goes, this description agrees with our specimens. 

The structure of the soft parts is essentially like that of the foregoing species 
(lentiformis and paraguayana). It should be remarked that the palpi are rather 
large, with a somewhat longer posterior truncation, and the posterior margins are 
connected at the base. Anal opening practically smooth. Papillze of the branchial 
opening very small. 

In the gravid female the whole inner gill is charged, with exception of the 
outermost extremities. The swelling of the marsupiwm is very moderate, and in a 
cross-section (Pl. XLVIII, fig. 7b) it is seen that only the part of the septa, extend- 


582 MEMOIRS OF THE CARNEGIE MUSEUM. 


ing from the swellings, toward the inner lamina (secondary limb) stretch out, and 
that the egg-masses are located only in this part of the water-tubes, while the 
part toward the outer lamina (primary limb) does not contain eggs, and forms 
what should be called secondary water-tubes. In the sterile female the swelling 
of the septa (vertical ridges projecting into the water tubes) are located as usual. 
In the cross-section of the gills of the male (Pl. XLVITI, fig. 7a) it is seen, chiefly 
in the inner gill, that the alternation of stronger and weaker septa is due to the 
alternating presence or absence of a larger blood-vessel at the point where the 
septum connects with the primary limb. In the marsupial gill of the female this 
is obscured in the direct view by the development of the ridges, so that the septa 
appear more uniform. 

The contents of the charged marsupium consist of small globular embryos in 
an early stage of development. No lasidia were seen. Von Ihering (1891, p. 
480) mentions the eggs of Aplodon pazi. They are small, 0.075 mm. in diameter. 


45a. MONOCONDYL#A MINUANA PARCHAPPI (D’Orbigny) (1835). 
Monocondylea parchappi D’OrBrIGNy, 1843, p. 615, Pl. 68, figs. 1-3; Smmpson, 

1900, p. 911; 1914, p. 1386; Haas, 1916, pp. 24, 54. 

Type-locality.—Rio Parand, Itaty, Province Corrientes, Argentina. 

Other Locality.—Rio Uruguay, Salto Oriental, Uruguay (Haas). 

New Locality.—Rio Jacuhy, Cachoeira, Rio Grande do Sul, Brazil (J. D. Hase- 
man coll., January 26, 1909). One specimen, male with soft parts. 

Distribution.—Rio Parand and Rio Uruguay, and also Guahyba-drainage. 
The distribution resembles that of MW. minuana. 

D’Orbigny has already pointed out the close resemblance of this form to M. 
minuana, but gives as differentiating characters the greater compression of the 
shell, the less elevated and less incurved beaks, the absence of a lunula, and the 
rose-colored nacre. We may dismiss the last two characters as unimportant, 
since the lunula is variable and generally less developed in forms with lower beaks; 
and since reddish nacre is found as an individual variation in other species of 
Monocondylea. But the greater compression of the shell and the feebler develop- 
ment of the beaks is striking. In D’Orbigny’s figure, as well as in my specimen, 
the latter character is connected with a straighter hinge-line, which is much less 
incurved below the beaks. 

We have seen that specimens of minuana sometimes approach parchappi in 
the less pronounced obesity. The same may be said of the inflation of the beaks 
and the curvature of the hinge-line. However, none of my specimens recorded as 


ORTMANN: SOUTH AMERICAN NAIADES. 583 


minuana from Cachoeira have the beaks as low and the hinge-line as straight as 
the specimen placed under parchappi. But there is no question that they incline 
in this direction, and that beaks and hinge-line are quite variable in minuana. 
Thus these two forms should be regarded as varieties of one species, actually con- 


nected by intergrades. 
MEASUREMENTS. 


Sex. | Length. | Height. Diameter. Beaks. | Greatest Height. 


a 


of | 41mm. lz9 mm. =71 pr. et. of L. 17 mm. =41 pr. ct. of L. at 12 mm. =29 pr. ct. of L. | at 26 mm. =63 pr. ct. of L. 


According to D’Orbigny, parchappi has a height of 64 pr. ct. and a diameter of 
43 pr. et., so that length and diameter are a little greater than in my specimen. 

Anatomy.—The specimen at hand is a male according to the soft parts. The 
structure is absolutely identical with that of the males of M. minuana. 


46. MonoconDYL®A OBESA Ortmann, sp. nov. 
Shells: Plate XL, figs. 4, 5, 6. 

Type-locality—Rio Tapajos, Santarem, Para, Brazil (J. D. Haseman coll., 
December 6-12, 1919). Type-set: Carn. Mus. Cat. No. 61.5850. Seventeen com- 
plete shells and a number of odd valves. 

Characters of Shell.—Shell small to medium in size (maximum length 57 mm.), 
moderately thick, outline briefly subelliptical, subovate, or subrotund (when 


young), hardly oblique. Height 75 to 86 pr. ct. of the length. Valves not gaping. 


Dorsal margin behind the beaks gently curved or almost straight, subconcave and 
very short in front of the beaks, passing gradually or at an indistinct angle into 
the anterior margin. Posteriorly the dorsal margin passes by a blunt, indistinct 
angle, or almost gradually, into the posterior margin, which descends obliquely 
and is gently curved. At the lower posterior end, which is little elevated above 
the base line, the posterior margin passes in a stronger curve into the lower margin. 
Lower margin very gently curved in its posterior part, sometimes almost straight 
and subparallel to the upper margin, so that a lowest point cannot be located. 
From about the middle it slopes upward, increasing the curve until it passes into 
the anterior margin. Thus the anterior part of the shell appears only little narrower 
than the posterior. 

Valves very convex, convexity rather uniform over the disk, slightly stronger 
over the posterior ridge, which is indistinct. The posterior slope is very slightly 
compressed, without forming a wing-like expansion. Diameter 60 to 69 pr. ct. 
of the length. Beaks much swollen and inflated, incurved, strongly elevated over 


584 MEMOIRS OF THE CARNEGIE MUSEUM. 


the lunula, and distinctly higher than the posterior upper margin, located at 28 to 
33 pr. ct. of the length. Lunula cordiform, short and broad, almost as broad as 
long. 

Epidermis dull, with crowded, irregular, concentric lines. My specimens 
being all dead shells, the original structure is somewhat doubtful, but in some speci- 
mens there are distinct indications of a lamellar, cloth-like structure. No radial 
sculpture present, and no distinet radial rib upon the posterior slope. Color of 
epidermis paler or darker brown, rather uniform, often with a more or less distinet 
blackish ray upon the posterior slope, sometimes accompanied by a second ray. 

Hinge-line gently curved or almost straight behind the beaks. Under the 
beaks it is sinuated, curving down more or less strongly, and then it is straight or 
may curve up a little, rendering the lunula slightly coneave. Pseudocardinal 
teeth of the usual type, but somewhat variable; that of the right valve in particular 
may be more or less compressed. Ligamental sinus rather small, triangular, its 
anterior margin oblique. 

Nacre white, shining in well preserved shells, iridescent, and with rather dis- 
tinet radial lines. Prismatic zone narrow, without any trace of a sudden widening. 
Cavity of shell and beaks considerable. Anterior adductor-sear deeply impressed. 
Anterior retractor-scar small, close to the adductor-sear, but distinctly separated 
from it. Anterior protractor-scar united with adductor-secar. Posterior adductor- 
sear faint, subovate, with a triangular upper process formed by the posterior 
retractor-scar. No dorsal scars. Pallial line subconcentric to the margin. 


| Height. Diameter. | Beaks | Figured. 


No | Length. 
Lieve | 22mm. | 18 mm. =82 pr. ct. of L. | 14 mm. =64 pr. ct. of L. at’ 6.5 mm. =30 pr. et. of L. Pl. XL, fig. 6. 
See | Spee! ode = 36 ‘ 19 “ =68 at Ss “ =29 ‘ [Eo bray, iss fa 
a 30 “ |25 “ =83 ub 18 “ =60 Wo sf 3G =30 “ | 
10. | AIR te: By Se) fo 27 =66 ie | ipyn 4? =e: S Pl. XL, fig. 4. 
11 | 49 39 =80 Sa Oo, 14 = 29 <A 
12 97 43 — ie f aHy Sail 16 a — 79 


Remarks.—There cannot be any mistake about this species, which differs from 
all others by the greatly swollen valves and inflated beaks, which render the shape 
almost subglobular. The diameter of 60 to 69 pr. ct. is not found in any other 
species of the genus, and approached only by M. paraguayana, which, however, 
distinetly differs in shape, being subangular, strongly oblique, and having the 
posterior slope much compressed and subalate. In addition, the present species 
differs from others by the narrow prismatic zone. It is impossible to give exact 
figures for the location of the greatest height, as the height of the shell is essentially 
the same for a considerable distance behind the middle. 


ORTMANN: SOUTH AMERICAN NAIADES. 585 


Only one of the described species comes near to the present one, and this is 
the little known M. inermis (Spix), as re-deseribed by Von Ihering (1890, p. 126, 
Pl. 9, figs. 1-3). This is founded upon a single, and apparently very young, in- 
dividual, which resembles to a degree our youngest specimens of obesa. Von Ihering 
gives the following figures for this: 
Length. Height. Diameter. 
21 mm. 15 mm.=71 pr. ct. of L. 10 mm. =48 pr. ct. of L. 


This specimen is not so high, and much less swollen than obesa, and we could 
not by any means place it at the head of our table of measurements. 


47. MoNocONDYL#A HOLLANDI Ortmann, sp. nov. 
Shell: Plate XLI, fig. 1. 

Type-locality—_Sand-bar of Rio Guaporé, near Rio Sao Simao, Matto Grosso, 
Brazil. (J. D. Haseman coll., July 20,1909). Type: Carn. Mus., Cat. No. 61. 
5846. One specimen, male, with soft parts. 

Characters of the Shell—Shell large (length 102 mm.) moderately thick, out- 
line subcircular, almost subrhomboidal. Height 77 pr. ct. of length. Valves 
very little gaping, almost closed in front.. Dorsal margin behind beaks practically 
straight, in front of them subconeave, short and much lower, passing by a very 
blunt angle into the anterior margin. The angle with the posterior margin is 
also very blunt, almost regularly rounded. Posterior margin obliquely descending 
and gently curved, passing in a sharper curve into the lower margin, thus forming 
the rounded posterior end of the shell, which is situated a good deal above the base- 
line. Lower margin curved, strongest curve in about the middle of the shell, 
forming a blunt lowermost point at 47 pr. ct. of the length (consequently a little in 
front of the middle). From this point the lower margin slopes up in either direc- 
tion; the posterior part of the margin is almost straight; the anterior more curved, 
and passes in a regularly increasing curve into the anterior margin. The anterior 
end of the shell cannot be called narrower than the posterior. 

Valves gently and regularly convex in the middle of the disk, and more so 
towards the beaks, distinctly compressed anteriorly and posteriorly, and the an- 
terior compression is quite remarkable, forming a sharp, elevated, almost wing- 
like expansion at the anterior upper margin. Posterior ridge of shell not at all 
marked. Diameter 45 pr. ct. of length. Beaks somewhat inflated, not very 
prominent (they are eroded), located at about 37 pr. ct. of the length. Lunula 
short and broad. 

Epidermis smooth, with irregular, concentric lines, poorly developed in the 


586 MEMOIRS OF THE CARNEGIE MUSEUM. 


middle of the disk and toward the beaks, slightly lamellar and more crowded on 
the posterior slope and near the lower margin. Upon the main part of the disk 
there are traces of indistinct radial lines. Posterior slope with an indistinct radial 
ridge. Color of epidermis yellowish brown, lighter in anterior half of the shell, 
darker in the posterior, the two colors divided by a rather distinct radial boundary- 
line through the middle of the shell. No color-rays are visible. 

Hinge-line straight behind the beaks. In front it is curved down, and then 
it slopes up again, making the lunula slightly concave. One pseudocardinal tooth 
in each valve, that of the left valve standing in front of, and slightly below, that 
of the right. The former is vertically depressed and projects into a slight groove 
of the right valve. This groove has a low horizontal ridge, fitting into a groove 
at the base of the upper face of the tooth of the left valve; however, this may be 
an individual character. Tooth of the right valve subpyramidal, not depressed, 
projecting and fitting into a groove which is partly under the margin of the left 
valve (the stumpy character of this tooth may also be individual). Ligamental 


sinus triangular, about as deep as wide, its anterior margin oblique to the hinge- 
line. 


Nacre white, not very iridescent,?° with hardly any traces of radial lines. 
Prismatic zone comparatively narrow, slightly wider in the anterior part of the 
shell, but not abruptly widening anywhere. 

Cavity of shell shallow, that of beaks moderate. Anterior adductor-scar 
sharply marked, elliptical. Anterior retractor-scar above it and close to it, but 
separated; in the right valve it appears double. Anterior protractor-scar con- 
nected with adductor-scar. Posterior adductor-sear less sharply marked, subovate, 
with a triangular process above formed by the posterior retractor-scar. No dorsal 
sears. Palhal line subconcentric to margin. 


M®&ASUREMENTS. 


= | 
2 Length Height Diameter. Beaks. Greatest Height. | Figured. 


o' 102 mm. 79 mm. =77 pr. ct. of L. 46 mm. =45 pr. ct. of L. at 38 mm. =37 pr. ct. of L. at 48 mm. =47 pr. ct. of L. Pl. XLI, 
| | | fig. ue 


Remarks.—A very striking and certainly new species, although only a single 
individual is at hand. It is much larger than any of the known species, and has 
a shape characterized chiefly by the location of the greatest height in front of the 
middle, and the absence of a distinet narrowing of the anterior part of the shell. 

“6 The nacre apparently is slightly corroded. Although the specimen was alive when found, and 
preserved with the soft parts, the uppermost layer of the nacre has been injured and is exfoliating. Ac- 


cording to my experience, this happens when specimens are allowed to die before they are put in alcohol. 


*\ 


ORTMANN: SOUTH AMERICAN NAIADES. 587 


It is also remarkable for the yellowish brown color of the epidermis, but this may 
be variable. In the relative dimensions it comes near M. lentiformis (height and 
diameter), and it is also a decidedly flat shell, although the beaks are slightly more 
inflated than in lentiformis. The compression of the anterior extremity also should 
be noted. 

I name this species in honor of Dr. W. J. Holland, Director of the Carnegie 
Museum, under whose auspices the expedition to Central South America by Mr. 
John D. Haseman was made. 

- Anatomy.—The specimen at hand is a male. 

Soft parts like those of the foregoing species, but the following points should 
be mentioned: the inner edge of the anal opening is practically smooth, that of the 
branchial opening with very minute papillae, which appear as mere crenulations; 
the gills have solid septa, which are unequal in thickness, heavier and lighter 
ones alternating in a more or less regular way, chiefly so in the middle of the gills. 


Genus ANopoNTITES Bruguiécre (1792). 
Anodontites BrucurbrE, Journ. Hist. Nat., Paris I, 1792, p. 131; Pinssry, 1911, p. 

609; OrTMANN, 191 1c, p. 91; Srupson, 1914, p. 1403. 

Patularia Swainson, Malacology, 1840, p. 287, 381. 
Glabaris GRAY (1847) Simpson, 1900, p. 916. 

In this genus the hinge is without any teeth. From Mycetopoda and Leila it 
differs by the absence of the characters peculiar to these, 7.e., in the shape of the 
shell, and certain features of the soft parts (See key p. 568). Furthermore we 
find in Anodontites an extreme variability in the shape of the shell, from rounded 
and subovate, to subtrapezoidal and elongated. The number of species is very 
ereat, and it is hard to arrange them. Simpson (1914) distinguishes three sections. 

1. Section Anodontites (sensu stricto). Shell rounded to elliptical; posterior 
ridge low or wanting. 

2. Section Styganodon Von Martens (1900). Shell subrhomboidal, with a 
thick, dark, rather rough, sombre-colored epidermis, which is sometimes faintly 
rayed; nacre lurid, shaded green. 

3. Seetion Virgula Simpson (1900). Shell subsolid to solid, moderately in- 
flated, greatly elongated, straight or faleate, rounded in front, sharply pointed 
at the posterior base, where the high, sharply defined posterior ridge ends, and 
above which it is somewhat obliquely truncated; beaks not high; epidermis green 
to olive; nacre brilliant, blueish or purplish, iridescent, rayed with very fine, in- 
distinct ridges; posterior end with a slight sinus. 


588 MEMOIRS OF THE CARNEGIE MUSEUM. 


It is seen at a glance that these three sections are not uniformly well defined. 
Virgula, indeed, is sharply separated from the rest. Styganodon is well character- 
ized by the epidermis; but unfortunately the type of the genus (A nondontites crispata) 
undoubtedly belongs to Styganodon, having an epidermis (thick, dark, rough, 
sombre-colored) which represents an extreme development of the Styganodon- 
structure; in other characters also, A. crispata is closely allied to A. tenebricosa,” the 
type of Styganodon. 

It is clear that, on the one hand, Anodontites (sensu strictiore) must be used for 
crispata, and, on the other hand, that Styganodon is a synonym of this, the type 
of the latter bemg closely related to crispata. This necessitates a re-arrangement 
of the sections, and a revision of their nomenclature. Although I have good 
material representing the genus, it is impossible for me to attempt a final classifi- 
cation, and the one given below is primarily adapted to the material at hand. An 
attempt is made to preserve Simpson’s groups as far as possible. 

Geographical distribution: The genus is widely distributed over South America 
east of the Cordilleras from Patagonia to the Caribbean Sea, being found also in the 
northern parts, where Diplodon and the Hyriine in general are rare, or absent. 
West of the Cordilleras it is generally missing, but it has been reported from that 
side in Ecuador (the fact, however, requires confirmation). In addition the genus 
has extended its range northward into Central America and Mexico, where it 
is found in both the Pacific and Atlantic drainages. 


Key tro THe Groups or ANODONTITES. 
a,. Shell not greatly elongated, nor pointed behind, without sharp posterior ridge. Posterior retractor- 
Scariconnectedawithvadductor-scarsaer eee nie eieacece aoe eee Subgenus Anodontites s. s. 
b,. Epidermis dull, densely wrinkled. 
c;. Shell more or less elongated, but not distinctly oblique and subcireular. 
d,. Shell subtrapezoidal, somewhat elongated. Lower margin straight or concave. 
Group of A. crispata. 
d». Shell subovate or subelliptical, rather short. Lower margin convex. 
Group of A. obtusa. 
cy. Shell distinetly oblique, short and high, nearly subcireular...........Group of A. trapezea. 
b». Mpidermis more or less shining, wrinkles only partially developed or absent. Shell straight or 
oblique, often distinctly so. 
cy. Shell not very oblique; straight, rather elongated, more or less pointed behind. Prismatic 
bordermarrow, or equallwidth: sera eee naeeeeeee eee Group of A. trigona. 
cy. Shell strongly oblique, not much elongated, not, or very little, pointed behind. 
d. Shell subovate or subrotund. Prismatie border wide, width unequal. 


Group of A. patagonica. 


*7 Another species, A. napoénsis, allied to crispata, has been placed in Styganodon by Haas (1916, 


pp. 32, 5: 


ORTMANN: SOUTH AMERICAN NAIADES. 589 


d». Shell subovate or subtrapezoidal. Prismatic border narrow and of equal width. 
Group of A. trapesialis. 
ds, Shell greatly elongated, sharply pointed behind, with a sharp posterior ridge. Posterior retractor- 
scar completely separated from adductor-scar.. Epidermis not shining, covered with fine wrinkles. 
Subgenus Lamproscapha. 

Subgenus ANODONTITES Ss. Ss. 

Anodontites s. s. + Styganodon Von Marrens, Simpson, 1914, pp. 1403, 1448. 

Shell of various shapes, but not greatly elongated or pointed behind, without 


sharp posterior ridge. Posterior retractor-scar connected with adductor-scar. 


1. Group of Anodontites crispata. 
Group of A. crispatus Srmpson, 1914, p. 1414 (pars) + Section Styganodon, group 

of A. tenebricosus, Simpson, ibid., p. 1448. 

Shell not, or very little, oblique, subtrapezoidal, rather elongated, with the 
lower. margin straight or more or less concave (sinuated). Epidermis dull, dark, 
not rayed, not smooth, but strongly and densely sculptured all over by concentric 
or radial, or irregular wrinkles. Prismatic border narrow or wider, of nearly equal 
width. 

The most essential feature of this group is in the texture of the epidermis, 
and its somber color. The nacre also is peculiar, being dull and lurid. 

These forms greatly resemble certain African species of Spatha, subgenus 
Aspatharia, and I am strongly inclined to think that of all South American types 
of Muteline these show the closest affinities to that African group. In A. crispata 

-oceasionally a single dorsal muscle-scar is present, which also agrees with the con- 
dition regularly seen in Spatha. 

Three species belonging here are known to me in nature. They may be dis- 
tinguished as follows: 


a,. Wrinkles of epidermis arranged concentrically and radially, the radial tendeney prevailing. Pris- 


TTL TAUCH EOC ETETHTO CELA GO Se cee, hc ayek es Sheics So eke cacao Settensl ecrentcur ny odo ial (ok abe wie piopeielenevern: aa 4. crispata. 

a>, Wrinkles of epidermis with concentric tendency prevailing, radial arrangement obscure. 
b,. Shell comparatively shorter and higher, beaks more median TMOS(ULO Me = et 4. tenebricosa. 
b». Shell comparatively longer and lower, beaks more anterior in POSItION see ts {. clessint. 


48, ANONDONTITES CRISPATA”® Bruguiére (1792). 
Shells: Plate XL, figs. 7, 8; Plate XLI, figs. 2, 3. 
Anodontites crispata Brucuiire, Journ. Hist. Nat. Paris, I, 1792, p. 131; SIMPSON, 
1914, p. 1415. 
Anodon reticulatus SowERBy, XVII, 1867, Pl. 10, fig. 27. 


28 Bruguiére uses Anodontiles as feminini generis, and this should not be changed. 


590 MEMOIRS OF THE CARNEGIE MUSEUM. 


Glabaris crispatus Stupson, 1900, p. 919. 

Type-locality—South America, 

Other Localities.—Cayenne (Lea, Syn., 1870, p. 106); Amazon River (Sowerby, 
reticulatus). 

New Locality.—Rio de la Paila, Paila, U. 8. of Colombia (C. H. Eigenmann 
coll., 1912). About twenty specimens, ten of them with soft parts, males and 
females. (The Rio de la Paila is a tributary of the upper Rio Cauca of the Rio 
Magdalena-drainage). 

Distribution.—Simpson says that this species is widely distributed in tropical 
South America, though but few exact localities are known. 

Characters of the Shell—Of medium size (maximum length 67 mm.), moder- 
ately thick, rather thin when young. Outline elongated subtrapezoidal, or sub- 
elliptical. Height 52 to 61 pr. et. of the length. Valves practically closed, or very 
little gaping in front. Dorsal margin straight, or prevalently very gently curved 
behind the beaks, descending in front of the beaks, and passing gradually into 
the anterior margin. Posteriorly it forms a blunt angle with the posterior margin, 
or passes into it in a curve. Posterior margin curved, obliquely descending in 
its upper part, becoming gradually steeper, and sometimes nearly vertical at the 
posterior end, which is blunt and rounded, but bends rather suddenly into the 
lower margin. The posterior end is thus very little elevated above the base-line, 
often practically at its level. Lower margin straight for a considerable distance, 
often even slightly concave in the middle, gently sloping upward toward the front 
and curving up into the anterior margin. This ascending part, and the descending 
anterior upper margin, make the anterior end of the shell narrower, but the whole 
shell does not appear very oblique. The highest part of the shell is in the posterior 
section. 

Valves moderately convex, rather flattened upon the sides, and sometimes 
even with a shallow depression corresponding to the emargination of the lower 
margin. Posterior ridge broad and rounded, indistinct, but the greatest diameter 
of the shell (31 to 88 pr. ct. of length) is situated upon it, so that the shell is more 
swollen posteriorly than anteriorly. Posterior slope slightly compressed, sometimes 
with a very faint radial groove. Beaks not swollen and not elevated above the 
hinge-line, located at 27 to 33 pr. et. of the length. Lunula indistinct or narrow, 
not very long. 

Kpidermis finely wrinkled all over, the wrinkles partly concentric, but pre- 
vailingly arranged in a radial pattern. Concentric and lamellar wrinkles are found 
chiefly near the margins. Upon the disk, the pattern varies in the anterior and 


ORTMANN: SOUTH AMERICAN NATIADES. 591 


posterior section of the shell. Anteriorly there are short, concentric wrinkles, 
arranged in scalariform, radial bands. Posteriorly the wrinkles are rather irregu- 
larly radial, assuming generally an oblique direction, forming radial bands of 
loops or V-shaped festoons, often anastomosing, and more or less reticular (“like 
dried paint’’). In the middle of the shell the two types of sculpture pass into each 
other: the short, subconcentric, scalariform wrinkles become rather suddenly V- 
shaped, and assume the oblique or radial direction. On the posterior slope and 
near the lower margin, the wrinkled sculpture is more or less obscured by sub- 
lamellar concentric striz. Color of epidermis, in very young specimens, yellowish; 
later it becomes brownish olive or dark greenish to blackish, generally more brown- 
ish toward the beaks, and more blackish toward the margins. Sometimes (in 
strong transmitted light) there are dark color rays upon the posterior slope. 

Hinge-line nearly straight or gently convex posteriorly, descending anteriorly, 
a little irregular just in front of the beaks. Ligamental sinus moderate, triangular, 
wider than deep, its anterior margin slightly oblique to the hinge-line. Nacre 
blueish white, grayish white, lurid, often showing brownish or greenish discoloration. 
Prismatic border rather narrow, subequal in width, of grayish color. 

Cavity of shell and beaks shallow. Anterior adductor-secar well marked, im- 
pressed, irregularly elliptical. Anterior retractor-scar only partially separated 
from adductor-sear, connected with it narrowly or more broadly, and very variable 
in this respect. Anterior protractor-scar separated from adductor-sear. Pos- 
terior adductor-scar less impressed, rounded or subovate, posterior retractor- 
sear forming an upper process of it. Dorsal sears generally absent, but in a few 
eases there is an indistinct single one. Pallial line distinct, simple, subparallel 
to the margin. 


MEASUREMENTS. 
No. Sex. Length. Height. | Diameter. Beaks. Figured. 
| } 
ores .| o 24.5mm./15 mm.=61 pr. ct. of L.| 8.56 mm. =35 pr.ct. of L. at 7 mm. =29 pr. ct. of L. 
? 37 LOS <5 53 - 11.5 “ =31 7 10 “ =27 ° Pl. XLI, fig. 3. 
2: Q |45 a Br Ae ad ) a 17 eo HS Lipa: 30 a 
5. ig). ae es 19:5e 35 3 15. 2) =27 s 
MO ee Oo 68:5 “* 135, C= 22 30) ie £35 = 28. % Pl. XL, fig. 8. 
[Eg Gece Sg Ra ae PP EGER es eer 19 “ =28 as Pl. XLI, fig. 2. 
Simpson..... 53 ahegp! US = > 17 5 =92, z= 


Remarks.—I have no doubt that my specimens represent A. crispata. They 
agree fairly well with Sowerby’s figure of Anodon reticulatus, and very well with 
Simpson’s description. But there are several closely allied, if not identical, species, 
chiefly A. napoénsis Lea (Obs. XII, 1869, Pl. 53, fig. 187, and Germain, 1910, p. 
C 64, Pl. 2, figs. 3, 4) from Rio Napo (tributary to the upper Amazon in Ecuador) 
and Rio Unuyacu (tributary to Napo). This species differs chiefly in the posterior 


rc 


592 MEMOIRS OF THE CARNEGIE MUSEUM. 


end of the shell, which is more elevated above the base-line, and in the more curved 
ventral margin. The sculpture of this species undoubtedly is similar, but the 
details have not been described. 

Simpson says that this species is very variable in sculpture. However, I 
find that my specimens (twenty at hand) are rather uniform in this respect. Only 
in the youngest specimen is the subradial sculpture of the posterior part not so 
well developed; but in the second (37 mm. long) it is distinetly seen. 

There is a good deal of variation in the shape of the posterior end, and the 
posterior margin may be more oblique or may be more vertical in its lower part. 
Very often the nearly vertical truncation of the posterior end produces the ap- 
pearance of a biangulation, chiefly when the faint groove of the posterior slope is 
visible. 

Anatomy.—Soft parts of six males and four barren females at hand for study. 
Anal opening separated from the branchial by a mantle connection, open and 
nowhere closed, its inner edge smooth or nearly so. Branchial opening with fine 
papillz. Palpi longer than high, lower margins convex, posteriorly truncated, 
the truncation forming the short posterior margins, which are connected at base 
only. 

Gills of medium width, the inner the wider anteriorly, its anterior end im- 
mediately behind the palpi, and attached to the whole interval between the palpi 
and the anterior end of the outer gill. The latter at the highest point of the mantle- 
attachment-line. Inner lamina of inner gill entirely connected with abdominal 
sac. 

Gills with well developed septa. In the non-marsupial gills the septa are 
irregularly alternating, stronger and weaker. In the female the inner gill is mar- 
supial for nearly its whole length, with stronger and more uniform, but not more 
crowded, septa. The septa possess the usual swelling, forming vertical ridges 
projecting into the lumen of the water-tubes, dividing the latter into an inner 
compartment (ovisac), and an outer (secondary water-tube). 


49. ANODONTITES TENEBRICOSA (Lea) (1834). 


Anodonta tenebricosa Lua, Obs., I, 1834, Pl. 12, fig. 36; D’OrBiaNy, 1843, p. 616. 

Anodon tenebrosa SowERBY, XVII, 1867, Pl. 13, fig. 43. 

Anodon tenebricosa SowERBY, XVII, 1870, Pl. 31, fig. 123. 

Anodonta tenebricosta Corst, 1901, p. 457, fig. 58. 

Glabaris tenebricosa VON InmrRING, 1893, p. 61; Nenrina, 1893, p. 163; SIMPSON | 
1900, p. 98 


ORTMANN: SOUTH AMERICAN NATADES. 593 


Anodontites tenebricosus Stmpson, 1914, p. 1448. 
Anodontites (Styganodon) tenebricosus Haas, 1916, pp. 35, 57. 

Type-locality.—Rio Parana. 

Other Localities —Rio San José and Arroyo del Rosario, Uruguay (D’Orbigny) 
(tributaries to La Plata in the Banda Oriental); Rio de la Plata, Buenos Aires, 
Argentina (D’Orbigny); Buenos Aires (Haas); Rio Uruguay, Salto Oriental, Uru- 
guay (Haas); Rio Piracicaba, Piracicaba, S40 Paulo, Brazil (Von Ihering) (Nehring). 

New Localities—Pond along banks of Rio Negro, Santa Isabel, Uruguay (J. 
D. Haseman coll., February 11, 1909). One complete specimen and one left valve. 
Rio de la Plata, San Isidro, 20 km. North of Buenos Aires, Argentina (A. Wind- 
hausen coll., January, 1917). One female with soft parts. 

Distribution.—From the region of Buenos Aires in the La Plata system and 
its tributaries in Uruguay (smaller streams of the Banda Oriental and Rio Uruguay- 
system) up the Parana River to its headwaters in Sao Paulo, Brazil. 

Simpson gives a much larger range, adding even Ecuador and Peru, but I do 
not know on what authority. 

This species is well known and has been well described. Its chief characters 
are its shape, which, although elongated-subtrapezoidal, is rather short and high 
in comparison with the related species. The prismatic border of the shell, chiefly 
in old shells, is remarkably wide, but subequal in width, not suddenly changing 
anywhere. 

The character of the epidermis has been given as concentrically lamellose. 
This is correct, and the fine, crowded, concentric lamellze are very obvious. How- 
ever, closer investigation shows that between these lamelle are additional, more 
irregular wrinkles, which produce upon the posterior part of the shell a reticulated 
(anastomosing) sculpture, and more anteriorly these wrinkles may be even radial. 
But they exist only between the concentric lamelle, and thus they are very short 
and largely obscured by the concentric sculpture. This difference of sculpture 
from that of A. crispata is very striking. Otherwise these two species have many 


features In common. 
MEASUREMENTS. 


Height. 


Sex. Length. | 


Diameter. | Beaks 
Sa sa belies ete ctatetst she a? 57mm. 33 mm. =58 pr. ct. of L. | 17 mm. =29 pr. et. of L. | at 18 mm. =32 pr. ct. of L. 
Salsidroph ots acce sce ao 92s 54 “ =59 He [tec fe ood ty 20 “ .=29 * 


According to Von Ihering’s measurements, the height is 53 pr. ct. and the 
diameter 34 pr. ct. of length. According to Nehring’s measurements the height is 
48 to 55 pr. ct., the diameter 30 to 33 pr. et. Thus specimens from the upper 


594 MEMOIRS OF THE CARNEGIE MUSEUM. 


Parani-drainage seem to be not so high, more elongated than those from the lower 
part of the system. In Lea’s original specimen (according to figure and measure- 
ments given by Simpson), the height is 55 pr. ct., the diameter 45 pr. ct. of length. 
In another specimen measured by Simpson, the height is 60 pr. et., the diameter 
38 pr. ct. D’Orbigny’s measurements give for height 58 pr. et. and for diameter 
37 pr. et. These latter figures agree very well with mine, and it should be noted 
that the larger specimens generally give a proportionally greater diameter. 

Anatomy.—The soft parts of one barren female are at hand for examination. 

Practically identical with the preceding species. The gills, in the present 
specimen, appear comparatively narrow. The structure of the marsupium (inner 
gill) is typical. The swellings of the septa are very distinct, and are situated closer 
to the outer lamina (primary limb). 


50. ANODONTITES CLESSINI (Fischer) (1890). 
Shells: Plate XLI, fig. 4; Plate XLI, figs. 1,2. Anatomy of gills: Plate XLVII, 
fig. 4. 
Mycetopus plicatus Cumsstn, Malakozoél. Blett., LI, 1882, p. 190, Pl. 4, fig. 7 

(nomen preoccupatum). 

Mycetopus clessini Fiscumr, Journ. de Conchyliol., XX XVIII, 1890, p. 8, footnote. 

Glabaris nehringi Von [aErinG, 1893, p. 60; Nerina, 1893, p. 163; Von InERING, 
1910, p. 139. 

Glabaris clessini Stupson, 1900, p. 930. 

Anodontites clessini Stupson, 1914, p. 1450. 

Type-locality: ? 

Other Localities.—Rio Sta. Maria, Rio Grande do Sul, Brazil (Von Ihering) 
(tributary to Ibicuhy and Uruguay); Rio Piracicaba, Piracicaba, Sio Paulo, Brazil 
(Von Thermg); Rio Piracicaba Mirim, Piracicaba, S40 Paulo, Brazil (Nehring); 
Rio Paraguassti, Bahia, Brazil (Von Ihering, 1910). 

New Locality.—Rio Vaccahy Mirim, Santa Maria (da Boeca do Monte), 
Rio Grande do Sul, Brazil (J. D. Haseman coll., January 29, 1909). Twelve speci- 
mens, all with soft parts, males and females. 

Distribution.—Positively known from the Uruguay drainage and the head- 
waters of the Parand. In addition, it has crossed over into certain coastal streams 
in Brazil. Our locality in Rio Vaccahy Mirim belongs to the Jaecuhy-Guahyba- 
system, but is close to Von Ihering’s record from the Uruguay drainage, but on 
the other side of the divide. This species has been found also in the Rio Paraguasstt 
in Bahia, well to the North, and separated from the rest of the range in the upper 
Parana (Piracicaba). But probably some kind of connection will be found. 


ORTMANN: SOUTH AMERICAN NAIADES. 595 


This species may be regarded as an elongated and narrow tenebricosa. In 
consequence of the general elongation, the posterior margin forms a more obtuse 
angle with the upper margin, and the posterior end is not subtruncated, but more 
evenly and narrowly rounded. Young specimens are almost regularly long- 
elliptical. The prismatic zone is comparatively narrow. The ligamental sinus is 
triangular, wider than deep, and its anterior margin forms an obtuse angle with 
the hinge-line (being directed obliquely backwards), or is almost vertical. (In 
A. tenebricosa this sinus is about as deep as wide, its anterior margin is nearly 
vertical and curved gently forwards, so that the lower point, which is quite sharp, 
is directed obliquely forward). 

In all other characters the two species resemble each other, and this is pre- 
eminently true of the sculpture of the epidermis. 


MEASUREMENTS. 


No. | Sex. | Length. Height. Diameter. Beaks. Figured. 
1..) &@ | 31 mm. |16 mm. =52 pr. et. of L.. 8.5 mm. =24 pr. et. of L. at 10 mm. =32 pr. et. of L. 

Asa p4by "122, “  =49 re 13 oO = be aS = 26 © 

Joico |S A Lag 3" ee yO 43 19 =31. a 17 “ =28 

Ie eu OSt ee \845 i =o0 ot 20 ae ss 19,“ =28 ms Pl. XLII, fig. 2. 
10. .| O69) Bh =45 is 23 ai if fs) 26 oa Pl. XLI, fig. 4; 
Ie eGOle us |S20° 5) © —=46 - 21 U2 ==840) 2 1 Se Pl. XLII, fig. 1. 


According to Von Ihering, the height is from 48 to 51 pr. ct., the diameter from 
22 to 33 pr. ct. of length, the beaks are at 24 to 31 pr. et. According to Nehring, 
the height is 41 to 48 pr. et., the diameter 20 to 25 pr. et. In A. tenebricosa, the 
figures for the height are 55 to 60 pr. et. (rarely below this); for the diameter 29 
to 45 pr. et. and for the beaks 29 to 34 pr. et. 

Remarks.—The greater length of the shell is brought out by these figures, 
and also the lesser obesity and more anterior position of the beaks, which results 
from it. It is also seen in my specimens that the elongation is not so great in 
younger specimens, and in the latter the measurements approach those of tenebricosa, 
or even fall within the range of variation of it. It is possible that the two species 
actually intergrade, a condition which has been hinted at by Nehring (p. 164) to 
exist in the Rio Piracicaba. 

Anatomy.—The soft parts of seven males and five barren females have been 
investigated. 

Color of soft parts whitish; inner edge of anal and branchial openings black, 
the black color running forwards from the branchial for a certain distance. 

Anal opening entirely open, its inner edge practically smooth, separated 
from the branchial opening by a connection of the mantle-margins. Inner edge 


596 MEMOIRS OF THE CARNEGIE MUSEUM. 


of branchial opening with distinet, but small papilla. Palpi rather small, semi- 
circular, shortly truncated posteriorly, thus forming posterior margins, which are 
not connected. 

Gills (Pl. XLVI, figs. 4a, b) long and narrow, the inner considerably wider 
than the outer, chiefly anteriorly. Anterior end of inner gill immediately behind 
the palpi. Inner lamina of inner gill entirely connected with abdominal sac. 
Septa well developed, those of the non-marsupial gills alternately somewhat stronger 
and weaker, best seen in the outer gill of the female (Pl. XLVI, fig.-4b). Inner 
gill of female marsupial for nearly its whole length, with more uniform, thicker, 
but not more crowded septa, which have the usual swellings near their contact 
with the outer lamina. 

2. Group of Anodontites obtusa. 
Simpson, 1914, p. 1453. 

Shell not very oblique, subovate or subelliptical, rather short, lower margin 
convex. Epidermis dull, greenish, often with rays, concentrically lamellarly 
wrinkled. Prismatic border narrow. 

The few forms belonging here are closely allied to the first group, and have 
indeed been placed in the section of Styganodon by Simpson. They are shorter, 
higher than those of the crispata-group, with more inflated beaks, and have an 
unusual development of color-rays. The seulpture of the epidermis is much like 
that of tenebricosa and clessini, and consists of close, sublamellar, concentric wrinkles, 
here and there subreticulated. 


51. ANODONTITES OBTUSA (Spix) (1827). 
Anodon obtusum Sprx, 1827, Pl. 22, fig. 3; Wacner, Ibid, p. 30. 
Anodon lituratum Sprx, Ibid, Pl. 22, fig. 4. 
Anodonta obtusa and litturata Hurt, 1857, pp. 86, 87, Pl. 17, fig. 4. 
Anodon obtusus SowERBY, XVII, 1867, Pl. 12, fig. 39. 
Anodon liturata SowErsy, Ibid, 1868, Pl. 20, fig.-78. 
Anodonta obtusa Von Inmrina, 1890, p. 159. 
Glabaris obtusus and lituratus Stmupson, 1900, p. 931. 
Anodonta (Glabaris) obtusa GERMAIN, 1910, p. 63, Pl. 3, figs. 14, 15. 
Anodontites obtusus and lituratus Simpson, 1914, pp. 1453, 1454. 
Type-locality.—Rio Paraguasst, Bahia, Brazil. 
Other Records.—Rio Paraguasstt (Von Ihering, 1910, p. 139); Rio Sao Francisco, 
Villa Nova, Sergipe, Brazil (Von Thering); Rio Sao Francisco, Joazeiro, Bahia, 
Brazil (Von Ihering); Rio das Velhas, Minas Geraes, Brazil (Von Ihering) (upper 


ORTMANN: SOUTH AMERICAN NAIADES. 597 


S. Franciseo-drainage); Bodegas, and Rio Daule, Ecuador (Germain) (Pacifie- 
drainage, near Guayaquil). 

New Locality—Lagoa Sacho Grande, Cidade da Barra, Bahia, Brazil (J. D. 
Haseman coll., December 24, 1907).. One young specimen. (8. Francisco- 
drainage). 

Another, larger specimen is in the Carnegie Museum, from the Holland Collec- 
tion, labeled “ Brazil.” 

Distribution.—Known from the drainages of Rio Paraguassi and Sao Fran- 
cisco. Von Ihering gives a possible variety, similar to the var. hohenackeri, from 
Rio Mucury, Bahia (southern part) (1890, p. 161), and another variety (juparana, 
1910, p. 131) from Lagoa Juparana.of Rio Doce, Espirito Santo).”’ The form 
is not known from the basin of the Amazon. So much more astonishing is Germain’s 
record of this species from the Pacific slope in Ecuador. I cannot discover any 
differences in these specimens, but attention should be called in this connection 
to A. aff. pastasanus of Haas (1916, pp. 34, 56, Pl. 2, fig. 1) which comes from the 
identical localities (Rio Daule and Bodegas in Ecuador). The latter, however, 
is more elongated than Germain’s figure of obtusa, and cannot be the same. 

Simpson also cites Paraguay, but I do not know on what authority. 

After what Wagner and Von Ihering have said, it is perfectly clear that liturata 
is the young stage of obtusa, and my larger specimen shows, near the beaks, the 
juvenile character of broken and oblique rays. Hupé says that litwrata is less 
swollen than obtusa, while Simpson (1914, p. 1454) states the opposite, that it is 
more inflated (possibly slip of the pen). Of my two specimens it is the smaller 
one, with liturata-color-markings, which is the more swollen. 


MEASUREMENTS. 


Length. | Height. Diameter. 


| Beaks 
Barra......| 36mm. |24 mm.=67 pr. ct. of L./17 mm.=47 pr. ct. of L.| at 12 mm.=38 pr. ct. of L. 
Brazil...... AT: 32 “ =68 a 119 ‘ =40 a oo ae 
Spix’ type..| 53 ‘ 35 “ =66 . Zt eee ees PS 


3. Group or ANODONTITES TRAPEZEA. 

Shell subcircular, but distinctly oblique, short and high. Epidermis dull, 
densely, concentrically, lamellarly wrinkled. Prismatic border moderate, or narrow, 
of nearly equal width. 

The subcireular shape and the dull, cloth-like epidermis are found in no other 
group combined. 


29 Tn 1910 (p. 131) he says that specimens from Rio Mueury are juparana. 


598 MEMOIRS OF THE CARNEGIE MUSEUM. 


52. ANODONTITES TRAPEZEA (Spix) (1827). 
Anodon rotundum and trapezewm Sprx AND WAGNER, 1827, p. 28, Pl. 20, figs. 1-4. 
Anodonta rotunda and trapezea Von InERING, 1890, pp. 142, 145, Pl. 9, figs. 5, 6. 
Anodonta cailliaudi Lma, Obs., X, 1863, Pl. 45, fig. 297. 
Anodon cailliaudi SowErBy, XVII, 1867, Pl. 12, fig. 38. : 
Glabaris rotunda Von Ta®rRING, 1893, p. 59; Stmpson, 1900, p. 918. 
Glabaris trapezea VON THHRING, 1893, p. 57; NEHRING, 1893, p. 163; Von InERING, 

1910, p. 138. 

Anodontites rotundus Simpson, 1914, p. 1410. 

D’Orbigny first recognized the identity of trapezea and rotunda, and selected 
the first name. Although the specimens from Corrientes, to which he applied 
this name, may not have been the typical trapezea, but a variety or even a species 
(spiai D’Orbigny, 1835), his selection of trapezea in preference to rotunda should 
be accepted. 

Type-locality.—Rio Solimodes (middle Amazon) Brazil. 

Other Localities.—Rio Sao Francisco, Villa Nova, Sergipe, Brazil (Von Ihering, 
trapezea); Sao Paulo, Brazil (Wagner, rotunda); Rio Piracicaba, Piracicaba, Sao 
Paulo, Brazil (Von Ihering, trapezea). 

This species, partly as rotunda, partly as trapezea, has been reported (D’Or- 
bigny, Lea, Von Ihering) from the lower Rio Parand (near Corrientes). However, 
the A. trapezea of D’Orbigny is believed to be a different form or variety (A. spixi 
D’Orbigny). It is surely allied to trapezea. 

New Localities —Lagoa de Sacho Grande, Cidade da Barra, Bahia, Brazil 
(J. D. Haseman coll., December 24, 1907). Six complete shells and four odd (left) 
valves. Lagoa de Sacho Pequeno, Cidade da Barra, Bahia, Brazil (J. D. Haseman 
coll., December 24, 1907). Three specimens, one a male with soft parts. Rio 
Grande, Barreiras, Bahia, Brazil (J. D. Haseman coll., January 4, 1908). Three 
males with soft parts. Rio Sao Francisco, Joazeiro, Bahia, Brazil (J. D. Haseman 
coll., February 28, 1908). One odd (left) valve. 

All these localities are in the drainage of the Rio Sao Francisco. 

Distribution.—The presence of this species in the system of Rio Sao Francisco 
is established. Since Von Ihering has also cited it as trapezea from the upper 
Parana (Piracicaba) in Sao Paulo, it must belong to both systems. Farther down 
the Paranda (Corrientes, Argentina) similar shells are present, but apparently 
slightly different from the type. The original locality is in the Amazon-drainage, 
but it has not subsequently been found there. 

Characters of the Shell.—Shell of moderate size (maximum length 75 mm.), 


ORTMANN: SOUTH AMERICAN NAIADES. 599 


rather thin when young, slightly more solid when older, but never of considerable 
thickness. Outline subcircular, but a little irregular and variable, and distinctly 
oblique. Height 80 to 93 pr. ct. of the length. Valves not gaping. Dorsal 
margin nearly straight. Posterior and anterior margins uniting with the dorsal 
in blunt angles. Posterior margin obliquely descending, first straight, then curved, 
and passing in a rather regular curve in the posterior part of the lower margin, 
without any trace of a posterior point. Lower margin ascending forward more 
strongly, and curving up into the anterior margin, so that the anterior part of the 
shell appears somewhat narrower than the posterior part, thus producing the 
obliquity. 

Valves inflated, diameter 49 to 56 pr. ct. of the length. Beaks somewhat 
swollen and inflated, elevated above the hinge-line and incurved, their tips im- 
mediately above the hinge-line in the young, a little higher in older shells. Loea- 
tion of beaks at 33 to 44 pr. et. of the length. Outer surface of shell rather regularly 
convex, but anterior and posterior slopes somewhat compressed. Posterior ridge 
quite indistinct. 

This species is remarkable for the presence of beak-sculpture, which is generally 
absent in this subfamily. However, I think that this sculpture is not genetically 
connected with that of other Naiades, but probably is independently developed. 
Quite a number of my younger specimens show it. The very tip of the beak ap- 
pears as a small tubercle, and is succeeded by three to five concentric bars, which 
follow the growth-lines, and are low and rounded, but perfectly distinct in the 
middle, disappearing anteriorly and posteriorly. These bars are restricted to and 
crowded together at the extremity of the beaks, and disappear at a short distance 
(3 to 4 mm.) from them. 

Epidermis with fine and crowded, concentric, somewhat anastomosing lines, 
which become lamellarly elevated toward the margins, and in well preserved shells, 
chiefly young ones, they have this character all over the shell. In addition there 
may be fine and faint radial striae, but there are no scalariform stripes. In old 
and partly worn shells the surface becomes rather smooth, but remains always dull, 
and is not shining. Color of epidermis from dark green to yellowish brown. The 
normal color in young specimens seems to be lighter or darker green, sometimes 
with indistinct dark green rays (seen only in transmitted light). In older specimens 
the color becomes greenish brown to light brown, due to partial abrasion of the 
epidermis. There are always two more or less distinet dark green or blackish 
rays upon the posterior slope, often accompanied by two lighter, yellowish rays. 
Larger specimens may have a few dark brown growth-rests. 


600 MEMOIRS OF THE CARNEGIE MUSEUM. 


Hinge-line practically straight in young shells; in older shells it curves gently 
down under the beaks, and up again at the anterior end, and the posterior end 
curves gently down, thus forming a slight S-curve. Ligamental sinus triangular, 
not deeper than wide, varying with age (shallower in young shells), its anterior 
margin running obliquely backward in the young, and vertically in older individuals; 
its lower point may be sometimes directed forwards. 

Cavity of shell and of the beaks rather deep, corresponding to the obesity 
of the shell. Nacre white; im young shells blueish white, in older shells somewhat 
inclining to cream-color, always extremely glossy, silvery, and iridescent toward the 
margins, with fine, straight, and irregular radiating lines. Along the margin there 
is a rather narrow nacreless (prismatic) zone, relatively wider in young specimens. 
This zone is subconcentric with the shell-margin, widest in the middle, gradually 
narrowing towards the ends, but nowhere suddenly or markedly changing its width. 

Anterior adductor-sear and anterior retractor-scar united, not deep, irregularly 
ovate or elliptical; anterior protractor-scar connected with adductor-sear, or, 
in old specimens, more or less (sometimes distinctly) separated. Posterior ad- 
ductor-scar faint, subovate, the posterior retractor-scar forming an upper pro- 
jection thereof. No dorsal sears. Pallial line subconcentrie to margin. 


MEASUREMENTS. 


Location. | No. | Sex. Length. Height. Diameter. | Beaks. 
Sacho Grande...., a ? 30) mm.24 mm.=80 pr. ct. of L. 15 mm, =50 pr. et. of L. | at 13 mm. =43 pr. ct. of L. 
Sacho Pequeno. . .| or 41 “134 ~ =83 i |} 21 “9 =51 " | 18 “ =44 * 
Barreiras...... 1 oa | 47 142 “  =89 > 24° =) ae 18) =38 : 

ERS a sasTosts 3 o | 54 “\47 “ =87 ey PLS tai) z | 20 “ =37 5 
Sacho Grande....| 6 2? | 58 “148 =83 a 30'S * 4=352 sf | 24 “ =41 ‘ 

Do. Le c ? 68 saeall Grek * =93 tn 33/0 OO 30 ‘“* =44 a 
Sacho Pequeno . ? T2:0) 16116," =85 4 38 “ =52 e 24 “ =33 2 
trapezea, type.............-| 63 ES en : -=39 s | (Von Thering) 
TOLUNAG, GYPCs ces seh sale : | 42 SO: S'S 65 «8 PPA aS) KS | Do. 
trapezea (Piracicaba) sell (0) "149 ee a Shp Gs e Do. 
rotunda (Simpson)..........| 75 “164 “ =85 oo 38 =51 7 | 


The variety (or species )spizi D’Orbigny from the lower Parana at Corrientes 
grows larger, reaching the length of 81 mm. according to Von Ihering, and of 90 
mm. according to D’Orbigny. 

Remarks.—This shell is easily recognized by the general shape and proportions, 
by the rather narrow prismatic border, and by the dull, greenish color of the epi- 
dermis. That trapezea and rotunda are only the old and the young stages of the 
same species, is conclusively shown by our material, chiefly by the sets from Cidade 
da Barra. The old specimens have the beaks a little elevated’ above the hinge- 
line, and the hinge-line is gently curved; while the young specimens have the point 


ORTMANN: SOUTH AMERICAN NAIADES. 601 


of the beaks immediately above the hinge-line, and have the latter straight. Speei- 
mens of intermediate size intergrade in these characters. 

Anatomy.—The soft parts at hand are not in good condition. However, the 
structure of the gills can be made out, and according to the alternation of stronger 
and weaker septa, all four specimens at hand are males. 

In other respects the usual structure of the genus is seen. Anal opening en- 
tirely open, separated from the branchial by a mantle-connection. Branchial 
opening with distinct, but small papillz. Palpi small, subcircular, with a short 
truncation at the posterior end; the posterior margins not connected. Inner lamina 
of inner gill entirely connected with abdominal sac. 


4. Group oF Anodontites trigona. 
Simpson, 1914, p. 1441. 


Shell not very oblique, rather elongated, subelliptical, or subovate, narrowly 
rounded, or somewhat pointed behind. Epidermis more or less shining, and not 
uniformly and densely covered with wrinkles, although such are present here and 
there. Prismatic border narrow, of nearly equal width. 

This group is poorly defined. Its chief character is the rather elongated shell, 
somewhat pointed behind, or narrowly rounded, and not distinctly oblique. The 
comparatively smooth epidermis is another noticeable feature, but still there are 
species, which have sublamellar, concentric stri, at least in parts of the shell. 
The color of the epidermis is not so sombre and dull as in the preceding groups. 
The narrow prismatic border seems to be constant. 


53. ANODONTITES TRIGONA (Spix) (1827). 
Anodon trigonum Sprix & WAGNER, 1827, p. 29. PI. 22, fig. 2. 
Glabaris trigonus Stueson, 1900, p. 92%. 
Anodontites trigonus Simpson, 1914, p. 1441. 
Anodon moretonianus SowERBY, XVII, 1867, Pl. 9, fig. 20. 

Doubtfully synonymous: 

Anodon georgine GrirritH, 1834, p. 595 (index), Pl. 19, fig. 3. 

A. moretonianus Sowerby undoubtedly is this species. Simpson (1914, p. 1431) 
is mistaken in placing it with A. trapesialis. Sowerby’s moretonianus is not A. 
mortoniana of Lea. 

A. georgine Griffith, from “rivers of Paraguay,” also seems to be this species. 
The figure given l.c. is shorter and higher, but the characteristic shape and the 
radial ribs (although too much emphasized) well agree with it. It is also from a 
region, where trigona is known to occur. For this species, Simpson (1900, p. 927; 
1914, p. 1440) creates a separate group. 


602 MEMOIRS OF THE CARNEGIE MUSEUM. 


Simpson makes Anodonta castelnaudi Hupé a synonym of trigona, but I do not 
think that this is correct. A. castelnaudi lacks the chief characteristic features of 
trigona: the pointed posterior end and the rib upon the posterior slope. 

Type-locality.— Rivers of the “province Rio Negro.” There is now no such 
province in Brazil, from which country the collections of Spix came. 

Other Localities.—Amazonas and Bolivia (Von Ihering, 1893, p. 120); Rio 
Xingu, Para, Brazil (tributary to lower Amazon) (Von Ihering, 1910, p. 137); 
Tributaries of Amazon in Bolivia (territory of the Chiquitos and Moxos) (D’Or- 
bigny); Rio Estacamento, Peru (Haas, 1916); Rio Paraguay, San Luis de Caceres, 
Matto Grosso, Brazil (Von Ihering, 1915, p. 13); Rio Batel and Rio Parana, Corri- 
entes, Argentina (D’Orbigny). 

New Localities —Swamp of Lambaré, Asuncién, Paraguay (J. D. Haseman 
coll., March 31, 1909). One right valve. Headwaters of Rio Paraguay, Santa 
Rita, Matto Grosso, Brazil (J. D. Haseman coll., June 12, 1909). Two specimens, 
male and female, with soft parts. Rio Limay, Patagonia, Argentina (W. Israél 
donor). One specimen. 

Distribution.—According to Von Ihering (1890) : ‘‘ Everywhere in the Amazonas 
region, but also in the La Plata up to Corrientes.’”’ Simpson gives: Brazil, Ecuador, 
Peru, Bolivia. The species undoubtedly has a wide distribution, both in the 
Amazon and the Paraguay-Parana drainages, but is apparently missing in the upper 
Parand. The new locality in Rio Limay in Patagonia (Rio Negro-drainage) con- 
siderably extends the southward range. 

Description of Shell—Shell rather thick and solid. Outline elongated-ovate, 
pointed behind, lower margin convex, forming a bluntly projecting angle about 
its middle. Height 59 to 61 pr. ct. of length according to my specimens (in D’Or- 
bigny’s the height is only 54 pr. et.). Valves not gaping. Dorsal margin gently 
curved, posterior part almost straight, anterior part descending. Posterior angle 
of dorsal margin obtuse, but well marked. Anteriorly the dorsal margin forms 
a very indistinct angle, or passes gradually into the anterior margin. Posterior 
margin descending obliquely, and almost straight or very gently curved, passing 
into the posterior part of the lower margin in a very sharp curve, which forms the 
posterior point of the shell. This point is somewhat elevated above the base- 
line, see the posterior part of the lower margin slopes upward. This part of 
the lower margin is almost straight. The lowermost point of the lower margin 
is a little behind the middle, and in front of it the lower margin changes its direc- 
tion, running upward and forward, so that this lower point forms a blunt projection. 
The ascending anterior portion of the lower margin is at first almost straight or 


ORTMANN: SOUTH AMERICAN NAIADES. 603 


very gently curved, and then it curves up into the anterior margin, which is narrowly 
rounded. The anterior part of the shell does not appear narrower than the pos- 
terior. The greatest height of the shell is a little behind the middle, and anteriorly 
it rather gradually becomes narrower, while posteriorly it tapers very decidedly 
to the posterior point. Thus there is also no marked obliquity in the shell. (In 
the young specimen from Santa Rita the posterior taper is not so strong). 

Valves moderately convex, diameter 34 to 36 pr. ct. of length. Beaks not 
very prominent above hinge-line, located at 18 to 26 pr. ct. of the length. Con- 
vexity of the valves greatest over the posterior ridge, least between this ridge and 
the region of the lower angle of the lower margin. Posterior slope compressed, 
but hardly any compression at anterior end. A distinet radial rib upon the pos- 
terior slope, lying between two radial depressions; sometimes there is a trace of a 
weak radial rib above it, but generally this is not very distinct. In young specimens 
the radial rib is indistinct. 

Epidermis rather smooth, with irregular concentric lines, which become 
lamellar upon the posterior slope and towards the ventral margin. No distinct 
radial sculpture, except some irregular and rather fine scalariform stripes. Color 
of epidermis normally a very dark green upon the disk, which, however, may turn 
to brown. The posterior slope may also be dark green, with the shallow grooves 
brownish, or it may be entirely brown, and in the young specimen it is brown, 
with the radial rib marked by a rather distinct dark green ray. The disk has no 
color rays. 

Hinge-line practically straight behind the beaks, and in front of them it 
gently curves down. Ligamental sinus triangular, about as deep as wide, its an- 
terior margin vertical to the hinge-line, or slightly descending backward. 

Cavity of shells and beaks moderate. Nacre whitish, more or less iridescent ; 
only in the young specimen with irregular and indistinct radial striae. Prismatic 
border rather narrow, subeconcentric with margin, and nowhere noticeably widened, 
except very slightly so in the region of the projecting part of the lower margin. 
Anterior adductor-scar well impressed, subovate, united above with scar of an- 
terior retractor. Anterior protractor-scar united with or separated from that 
of the adductor. Posterior adductor-sear faint, subovate, the posterior retractor- 
scar forming a triangular upper projection of it. Pallial line subeoncentrie to the 
margin. 

According to Wagner, the height would be 57 pr. ct. of the length. 

Remarks.—This species has a quite characteristic shape, which varies only 
slightly, and the most prominent features are the blunt angle of the lower margin, 


604 MEMOIRS OF THE CARNEGIE MUSEUM. 


the anterior position of the beaks, the sub-pointed posterior end, and the radial 
rib upon the posterior slope. The dark green color of the disk may also be charac- 
teristic, but this is liable to fade; in our specimen from Asuncién, a much-worn 


shell, the remnants of the epidermis are brown. 


MEASUREMENTS. 


Localities Sex Length Height. | Diameter. Beaks. 
Santa Rita... fof 386mm. 22 mm. =61 pr. ct. of L. | 13 mm. =36 pr. ct. of L. |jat 9.5 mm. =26 pr. ct. of L. 
Doser Q 62 “ | 37 “ =59 ee | 22°" = 35 (or © 18 
Limay...: ? 6845 A 0) Be ee  e==ahy a | 16 a ae : 
Asuncion. . . ? fA) eo 42, * =60 ve 24. -'\ = 34 * 16 =23 oh 
Spix’ figure . . Al 4S te of 36 
D’Orbigny’s figure -| Si! * | Sst! 


Anatomy.—The soft parts of a young male and a gravid female (collected 
June 12) are at hand for study. 

The typical Anodontites-structure is observed. The mantle-connection separat- 
ing anal and branchial openings is rather long. The branchial opening has ex- 
tremely fine papille. The inner edge of anal and branchial is brown. Palpi of 
medium size, semicircular, with a short posterior truncation. 

In the gravid female the eggs fill the water-tubes of the inner gill, with ex- 
ception of those near the extreme anterior and posterior ends. The water-tubes 
are markedly expanded, and the eggs are located in the basal part of the tubes, 
and only in the inner compartment (ovisac) toward the inner lamina of the gill. 
No larvee were seen. The outer gills have the usual structure of alternately thicker 
and thinner septa, while the septa of the inner gill are more uniform and thicker. 
The gills of my female are much torn and injured, so that it was not expedient to 
section them. 

54. ANODONTITES HYRIOIDES Ortmann, sp. nov. 
Shells: Plate XLII, figs. 3, 4, 5. 


Type-locality—Rio Tapajos, Santarem, Para, Brazil (J. D. Haseman coll., 
December 6-12, 1909). T'ype-set: Carn. Mus. Cat. No. 61.5829. Six specimens. 

Characters of the Shell—Shell moderately thick, angularly subovate, some- 
what oblique, pointed behind, lower margin convex, forming a blunt angle. Height 
62 to 75 pr. et. of the length. Valves not gaping. Dorsal margin practically 
straight, gently descending in front of the beaks. Posterior angle of dorsal margin 
obtuse, but quite distinct, wing-like. Anteriorly the dorsal margin forms also a 
more or less distinct angle, which is obtuse or almost a right angle. Posterior 
margin obliquely descending, straight, or slightly concave in its upper portion, 


ORTMANN: SOUTH AMERICAN NAIADES. 605 


curving sharply around into the lower margin, thus forming the posterior point of 
the shell. This point is only a little elevated above the base-line, since the pos- 
terior part of the lower margin runs straight forward, being almost parallel to 
the dorsal margin (there is some variation in this respect; on the average these 
two margins diverge very slightly towards the front). From a point at, or slightly 
behind, the middle of the shell the lower margin changes its direction abruptly, 
running forward and upward, thus forming a lower blunt angle at about the middle 
of the shell. The ascending anterior part of the lower margin is first almost st raight, 
but then it passes in a curve into the anterior margin, which is narrowly rounded. 
The shell appears slightly narrower anteriorly, with the greatest height in the pos- 
terior part. The taper of the posterior end is stronger than in A. trigona, and thus 
the shell appears somewhat oblique. 

Valves more convex than in A. trigona, diameter 38 to 46 pr. ct. of the length. 
The greatest swelling is towards the beaks, but the beaks are not much elevated 
above the hinge-line, so that they appear rather depressed. Location of beaks 
at 27 to 31 pr. ct. of the length of the shell. The convexity of the valves is like 
that of A. trigona, compressed upon the posterior slope, and flattened in front of 
the posterior ridge. Posterior slope with one or two more or less distinct radial 
ribs, accompanied by shallow depressions. 

Epidermis similar in sculpture to that of A. trigona, but more frequently 
with fine sealariform stripes, chiefly upon the anterior part of the shell, producing 
the appearance of fine radial sculpture. Color of epidermis from dark or light 
ereenish and yellowish to light or dark brown; one specimen inclines more toward 
olive-green. Most of the specimens are somewhat concentrically banded with 
lighter and darker color. 

Hinge-line straight behind the beaks, melining downward in front of them, 
but very little so in the youngest specimens. Ligamental sinus triangular, shaped 
like that of A. trigona. 

Cavity of shell moderate, that of beaks somewhat deeper. Nacre whitish and 
iridescent, with indistinct radial strize. Prismatic zone narrow, subeconcentrice 
to the margin. Muscle- and mantle-scars as in A. frigona. 


MEASUREMENTS. 


No. Length. Height. Diameter. Beaks Figured. 


1 32 mm. | 22 mm. =68 pr. ct. of L. 14 mm. =44 pr. ct. of L. at 10 mm. =31 pr. ct. of L. Pl. XLII, fig. 5. 
2... 33 24 “ =73 ie 14 “ =42 oH OPS .=27 > 
Oe: ‘ olay 27 “ =66 * 16, =. =39 - 12 =29 i 
pel Wa a 26 “ =62 * 16 “ =38 zi 12 =29 = Pl. XLII, fig. 4. 
Be op 42: = 29 “ =69 + 17 “ =40 oe 12 =29 ” 
Gece oti. 33“ =64 - 24 ‘ -=46 * 14 =p 7 Pl. XLII, fig. 3. 


606 MEMOIRS OF THE CARNEGIE MUSEUM. 


Remarks.—This species undoubtedly is closely allied to A. trigona, and dif- 
fers chiefly in the dimensions. It might be a local variety of it, but since all six 
of my specimens are rather uniform in their characters, I take it for a species. 

A. hyrioides is an A. trigona, which is higher and shorter, more inflated, has 
the outline more sharply angular, and is more oblique. The obliquity is due to 
the shortening of the shell and the lower position of the posterior point. The out- 
line of our species recalls the shape of the genus Hyria, and hence the name. 


55. ANODONTITES MORTONIANA (Lea) (1834). 


Anodonta mortoniana LHa, Obs. I, 1834, Pl. 13, fig. 37. 

Anodonta weddellii Hur, 1857, p. 87, Pl. 17, fig. 5. 

Anodonta lingulata Hurst, 1857, p. 89, Pl. 18, fig. 1. 

Anodon weddellii and lingulata SowErBy, XVII, 1868, Pl. 20, fig. 80; 1869, Pl. 23, 

fig. 90. 

Glabaris mortoniana and lingulata Von THERING, 1893, p. 118, 119. 
Glabaris weddelli, lingulatus, and mortonianus Simpson, 1900, pp. 928, 929. 
Anodontites weddelli, lingulatus, and mortonianus Simpson, 1914, pp. 1442-1445. 

Type-locality—River Parana. 

Other Localities.—Santa Ana de Chiquitos, Bolivia (Hupé, weddelli) (situated 
about on the divide between the drainages of the Paraguay and the Amazon); 
Corumbi, Matto Grosso, Brazil (Hupé, lingulata); Rio Paraguay (Von Ihering); 
Lower Parana (Von Ihering). 

New Localities —Mountain creek, Sapucay, Paraguay (8. E. of Asuncién) 
(J. D. Haseman coll., April 5, 1909). One male with soft parts. Headwaters of 
Rio Paraguay, Santa Rita, Matto Grosso, Brazil (J. D. Haseman coll., June 12, 
1909). ‘Two specimens, one a male with soft parts. 

Distribution.—This species apparently belongs to the Paraguay-drainage and 
the Rio Parana below its union with the Paraguay. Von Ihering (1893, p. 114) 
does not mention any of the forms belonging to this species from the upper Parana. 

Remarks as to Synonymy.—The three forms, mortoniana, weddelli, and lingulata, 
are kept as separate species by Simpson, but I do not see any essential differences 
between them. 

Hupé admits that weddelli is very close to mortoniana, but says that it differs 
in three respects: more swollen shell; narrower and more rounded anterior end; 
and deeper and larger muscular impressions. These differences are not sub- 
stantiated by the figures, in fact, we cannot judge as to the first, since no figure 
showing the obesity is given. According to the measurements in the text, how- 


ORTMANN: SOUTH AMERICAN NATIADES. 607 


ever, just the opposite is the case, mortoniana being more swollen (40 pr. ect.) than 
weddelli (33 pr. ct.). The second difference is not at all correct according to the 
published figures; and the third apparently is founded only upon the slight indica- 
tion of the muscle-scars in Lea’s figure, and is not essential, anyhow. Besides, 
Hupé says that the specific difference is supported by the different distribution 
of the two forms. This again is not evident. A. weddelli is from the region of 
the divide between the Amazon and Paraguay-drainages, and it may very well be 
from the latter. One of our localities is not very far from it. A. mortoniana and 
weddelli, indeed, have been united already by Von Ihering (1893, p. 118). 

A. lingulata differs from the others only in size and the color of the epidermis. 
The latter, on the plate, is dark green, while the text says that it’is blackish brown, 
and thus we cannot rely on it. The shell of lingulata is more regularly elliptical, 
but this is not astonishing when we consider the greater age of this shell. It is 
also from the same general region (upper Paraguay) as mortoniana and weddelli. 

Very similar forms are found also in the Amazon-drainage: castelnaudi Hupé, 
solidula Hupé, amazonensis Lea, and elongata Swainson. But these cannot be 
united with mortoniana, since they all are more elongated. 

Characters of the Shell.—Shell quite thick and solid. Outline subovate or 
nearly subelliptical, bluntly pointed behind, lower margin gently convex. Height 
61 to 63 pr. ct. of the length, falling, in old specimens, as low as 53 pr. ct. Valves 
not gaping. Dorsal margin gently convex; the part behind the beaks may be 
almost straight; in front of the beaks it descends more or less. Posteriorly the 
dorsal margin forms a blunt angle, or may pass almost insensibly into the posterior 
margin. There is no distinct angle anteriorly. Posterior margin obliquely descend- 
ing, more or less convex, curving into the lower margin and forming with it a dis- 
tinct, but rounded, posterior point of the shell, which is situated at a certain eleva- 
tion above the base-line, but nearer to the latter than to the line of the upper margin. 
Lower margin gently and rather regularly curved, ascending somewhat toward 
the posterior end of the shell, and more strongly so in its anterior part, where it 
passes in a regular curve into the anterior margin. The anterior part of the shell 
is only slightly narrower than the posterior, which is widest (highest) a little behind 
the middle of the shell, and then tapers gently toward the posterior point. The 
shell is thus transverse, and hardly oblique. 

Valves moderately convex, diameter 37 to 41 pr. et. of the length (weddelli is 
more compressed, 33 pr. ct.). Beaks moderately convex, not very prominent above 
hinge-line, at 23 to 25 pr. ct. of the length, that is to say, rather anterior. Convexity 
of valves rather uniform all over the disk, strongest over the posterior ridge, slightly 


608 MEMOIRS OF THE CARNEGIE MUSEUM. 


compressed upon the posterior slope. Posterior slope with one or two blunt 
radial ribs, which may be more or less distinet, or almost effaced. 

Epidermis rather smooth, with irregular concentric lines, which become sub- 
lamellar upon the posterior slope and near the lower margin. Traces of radial 
sculpture are present in the shape of fine scalariform stripes, irregularly disposed 
upon the shell, and more or less numerous. Color of epidermis brownish or green- 
ish. Upon the disk it may be quite green (dark or light), or it may be darker or 
lighter brown, with irregular concentric bands of dark green. The posterior slope 
is (In my specimens) always light brown, with or without greenish tints. No 
color-rays are seen. 

Hinge-line gently curved. In the younger specimens the part behind the beaks 
is straight; in older ones it is gently curved, and curves down more distinctly under 
the beaks. Ligamental sinus triangular, about as deep as wide, its anterior margin 
vertical to the hinge-line. . 

Cavity of shell and beaks moderate. Nacre -whitish, iridescent, only in the 
youngest specimen with faint traces of radial strize. Prismatic zone very narrow 
(comparatively widest in the young), subeoncentrie to the margin. Anterior 
adductor-sear well impressed, chiefly in the older shells, subovate, united above 
with the anterior retractor-scar. Anterior protractor-scar united with, or free 
from, adductor-sear (this may be different in the right and left valves of the same 
shell). Posterior adductor-sear less impressed, subovate, the posterior retractor- 
sear forming an upper triangular projection of it.  Pallial line subeoncentric to 


lower margin. 
MBASUREMENTS. 


Length. Height. | Diameter. Beaks. 
Santa Rita... 52mm.) 33 mm.=68 pr. et. of L. |20 mm.=38 pr. ¢t. of L.| at 18 mm.=25 pr. ct. of L. 
HAPUCHY tee Oe ee tae 0 Ol ss | 20 ol S | 1 sae ee - 
Santa Rita...69 “ |42 “ =61 ke [Qe ms i) 4 SS as 


Lea’s measurements for mortoniana give for the height 53 pr. et. and for the 
diameter 40 pr. et. of the length. Thus the height is less here, but I think this 
is due to the greater age of this specimen. My largest specimen has a peculiar 
shape: the posterior end of the shell is drawn down, so that the lower margin is 
almost straight. This, however, undoubtedly is an individual character, since the 
growth-lines indicate that the young shell had the normal shape. 


The measurements for Hupé’s shells are as follows: 


Length. Height | Diameters. 


Wieddellace rss hth. teoeeace 66 mm. 33 mm.=53 pr. et. of L. 22 mm. =33 pr. ct. of L. 
Lingulata.......... Swan LOORS 2 Oe a 


ORTMANN: SOUTH AMERICAN NAIADES. 609 


The height of lingulata is given as 92 mm., but there surely is a mistake in 
this statement. According to the figure, it would be 53 pr. et. of the length. 

Remarks.—The characters of this species are its rather regular, subovate, 
or subelliptical, outline, with a blunt point behind, somewhat elevated above the 
base-line. The shell is not very long and of considerable thickness. The peculiar 
ereen in the color of the epidermis is remarkable, but is not always present. 

Anatomy.—The soft parts of two males are at hand for examination. 

The structure is typical of the genus. The papille of the branchial opening 
are very small. The inner edge of the anal and branchial is brown. The palpi 
are of medium size, semicircular, with a short posterior truncation, forming the 
posterior margins, which are not united. The septa of the gills are irregularly 
stronger and weaker. 


56. ANODONTITES HASEMANI Ortmann, sp. nov. 
Shells: Plate XLII, figs. 6, 7. 


Type-locality Headwaters of the Rio Paraguay, Santa Rita, Matto Grosso, 
Brazil (J. D. Haseman coll., June 12, 1909). Type-set: Carn. Mus. Cat. No. 
61.5832. Four specimens, among them two males and a gravid female with soft 
parts. 

Characters of the Shell.—Shell moderately thick, outline subovate, narrower 
in front, broader (higher) behind, not pointed. Height 63 to 67 pr. ct. of the length. 
Valves not gaping. Dorsal margin gently curved, the part behind the beaks almost 
straight; anteriorly to the beaks it descends distinetly, and passes into the anterior 
margin in an indistinct, obtuse angle. At the posterior end the upper margin forms 
a more distinct, obtuse angle. Posterior margin obliquely descending, gently 
convex, broadly curving around at the posterior end into the lower margin. The 
latter is gently curved, and runs forward and upward, being almost straight in 
the anterior part, finally curving up into the anterior margin. Thus the shell is 
distinctly narrowed anteriorly, the greatest height being located at about the be- 
ginning of the posterior third of the shell, and the shell bemg somewhat oblique. 

Valves rather convex, diameter 42 to 47 pr. ct. of the length. Beaks rather 
inflated, but only moderately elevated above the hinge-line, located at 27 to 33 
pr. ct. of the length. Convexity of valves rather regular, greatest over the posterior 
ridge, which is indistinct, very slightly compressed upon the posterior slope, with- 
out perceptible flattening upon the sides of the disk. Posterior slope with indistinct 
and faint traces of one or two radial ribs. 

Epidermis very slightly shining, with crowded, irregular, fine, subconcentric 


610 MEMOIRS OF THE CARNEGIE MUSEUM. 


lines, becoming lamellar upon the posterior slope and near the lower margin. There 
are hardly any traces of radial sculpture. Color olive-brown, rather uniform. 
The smallest specimen has a trace of a dark radial ray upon the posterior slope, 
otherwise there are no rays, nor indications of growth-rests. 

Hinge-line upon the whole gently curved, but the part behind the beaks is 
practically straight, chiefly in the younger specimens. The part in front is decurved, 
but in one specimen it distinctly curves up again at the anterior end. Ligamental 
sinus triangular, hardly as deep as wide, its anterior margin in the largest specimen 
being vertical, in the others slightly descending backward. 

Cavity of shell and beaks rather deep, corresponding to the obesity of the 
valves. Naere blueish white, with purple and green iridescence, and with very 
faint radial strize in the younger specimens. Prismatie zone quite narrow, sub- 
concentric with the margin. Anterior adductor-sear not very deeply impressed, 
subovate, united with the scar of the anterior retractor; scar of anterior protractor 
separated from it more or less completely. Posterior adductor-sear faint, sub- 
ovate, with an upper triangular process formed by the posterior retractor. Pallial 
line subeoncentrie with the margin. 


MEASUREMENTS. 


Sex. Length. Height. | Diameter. Beaks. Figured. 


No. | 
1 o | 45mm. 30 mm. =67 pr. et. of L.)19 mm. =42 pr. ct. of L.'at 15 mm. =33 pr. et. of L. Pl. XLII, fig. 6. 
Pel laton Die SOfe—Os) ¥ 24> 54? pe Vio wy 
Ole ore “| Ory G2i ee 39°“ =63 a Les, tn My | eee Fi 7 Pl. XI, fig, 7. 


4...) oy S| (GOreont 43065) as 31 “ =47 - = aifeye es aye sf 
| 


Remarks.—1 cannot find among the described species any one which agrees 
with the present form. Its chief feature is the broadly rounded posterior end. 
In this character and in the obliquity it resembles the species of the patagonica- 
group, but it differs from them in the prismatie border, which is narrow. I have 
placed this species in the trigona-group, although it has not the subpointed pos- 
terior end, because I could not conveniently place it anywhere else. Of other 
species, only A. obtusa resembles it to a degree, but the latter is somewhat shorter 
and higher (Height 64 to 69 pr. et. of L.), and not distinetly oblique, with the 
upper and lower margins more nearly parallel. Besides, A. obtusa has a peculiar 
color-pattern. 

Anatomy.—Soft parts of two males and one gravid female at hand. 

The structure is of the normal Anodontites-type. Papillee of the branchial 
opening very small. Gills with the septa well developed. In the gravid female, 
the inner gills have the usual marsupial structure, with a swelling at the insertion 
of the septa on the outer (primary) limb of the gill. The water-tubes contain 


'— ''? 


ORTMANN: SOUTH AMERICAN NATADES. 611 


eggs in their inner compartments, except at the anterior and posterior ends of 
the gill; the other compartments forming secondary water-tubes. The septa 
of the ovisacs are somewhat stretched out, and the gill is slightly distended. I 
was unable to find fully developed larve (lasidia?). All eggs are small, round, 
globular masses of cells (morula-stage), enclosed in a rather tough membrane. 
In the males no regular alternation of stronger and thinner septa could be noticed, 
but all septa are rather uniform. The male character, however, has been positively 
established by microscopic examination (absence of swellings of the septa). 


5. Group oF ANODONTITES PATAGONICA. 
Simpson, 1914, p. 1403. 

Shell strongly oblique, subovate or subrotund, not pointed behind. Epidermis 
more or less shining, but here and there with wrinkles, or covered all over with 
concentric striz. Prismatic border rather wide and unequal, being much wider 
along the anterior lower margin than at the anterior and posterior ends. 

The prismatic border forms the most prominent feature of this group. I 
possess a good number of specimens belonging to the group, and this character is 
always present, so that we must regard it as of taxonomic value. In addition 
the shell is here distinctly oblique with a rounded end. 


Key to THE Forms at Hanp. 

a;. Shell moderately inflated, diameter generally between 40 and 50 pr. ct. of the length, rarely less. 
Outline strongly oblique, moderately elongate, sometimes subrotund, height from about 65 to 
over 80 pr. ct. of length. 

b,. Shell thick, rather more elongated. Nacre whitish...........................A. patagonica. 
by. Shell thinner, subrotund or elongated. Naere often red.:............4 {. patagonica rubicunda. 

a». Shell compressed, diameter 36 pr. et. or less. Outline obliquely ovate, rather elongated, height not 
over 66 pr. ct. 

b;. Prismatie border wide and unequal. Epidermis shining, striae not sublamellar....A. puelchana. 
bo. Prismatie border narrower, but unequal. Epidermis not very shining, with the striz often 


siiloi evaa(allleteas 3 6 L2G olde cr reac OG CDT eRe Or RerOeaaO RCe ane ene ern” A. theringi. 


nar d 


57. ANODONTITES PATAGONICA (Lamarck) (1819). 
Anodonta patagonica LAMARCK, 1819, p. 88; Eneyelop. Method., II, 1827, p. 147, 

Pl. 203, fig. 1. 

Anodontites patagonicus Simpson, 1914, p. 1403. 

Remarks as to Synonymy.—The synonymy of this species has been given by 
Simpson, but it needs certain additions and corrections. The following references 
should be added first of all: 

Anodonta latemarginata and wruguayensis Corst, 1901, p. 454, 458. 


612 MEMOIRS OF THE CARNEGIE MUSEUM. 


Anodontites patagonicus Haas, 1916, pp. 25, 54. 

As we have seen above, Anodon trapezeum Spix (1827) should be stricken from 
the list of synonyms. This is a different species, differing chiefly by the narrow 
prismatic border. The other references given by Simpson all certainly belong here, 
and the following names have been used for this species: 

Anodonta latomarginata La (1834). 

Anodonta membranacea D’OrBIGNY (1843). 

Anodonta solida KurESTER (1853). 

Anodonta uruguayensis LEA (1860). 

Anodonta sinuosa CLESSIN (1873). 

Anodonta serpentina CLESSIN (1876). 

In addition: 

Glabaris bergi VON Ta RING (1893 p. 118), introduced for sinwosa Clessin. 

But the following forms also belong here as synonyms: 

Anodon crassus SWAINSON (1823); Srmpson, 1914, p. 1406. Simpson says: this 
species is “close to A. patagonicus, but I have never seen a specimen of that 
species quite so elongated or so pentagonal as the figure.’”’ The dimensions 
are: L. 80mm., H. 52mm. = 65 pr. et. of length, Diameter 32 mm. = 40 pr. ct. 
of length. These figures agree well with the dimensions of my series of speci- 
mens from San Isidro, some of which are even more elongated (height falling 
as low as 60 pr. ct. 

Anodonta wymani LEA (1860); Surpson, 1914, p. 1407, who says: ‘‘ More elongated 


’ 


and more richly colored than A. patagonicus.”’ The elongation is even greater 
than in A. crassus (Height = 63 pr. et. of length), but it still remains within 
the limits of variation of my set from San Isidro. Some of the latter un- 
doubtedly are wymani in every respect. The color is no reliable character, 
being very variable in A. patagonica. 

Tam unable to form an opinion as to A. sirionos D’Orbigny (1835) (= ferrarisi 
D’Orbigny, 1855). It certainly is nearly related to A. patagonica, but, according 
to the original description, is distinguished by a rough and concentrically and 
lamellarly striate epidermis. I have no specimens corresponding to this form. 

Type-locality.— Rio de la Plata and Patagonia. ; 

Other Localities —Rivers of Uruguay between Montevideo and Buenos Aires 
(D’Orbigny, membranacea); Rio Miguelete, Montevideo, Uruguay (Haas); Arroyo 
S. José, Uruguay (N. W. of Montevideo) (Corsi, uruguayensis); Uruguay River 
(Lea, uruguayensis, wymani); Rio de la Plata (Haas); Rio de la Plata, Buenos 

( 


Aires, Argentina (D’Orbigny, membranacea); Rio Parand (Lea, latomarginata): 
fon) eyo ) \ > >| 


ORTMANN: SOUTH AMERICAN NAIADES. 613 


Rio Parand up to sixty miles above Corrientes, Argentina (D’Orbigny, mem- 
branacea). 

Localities Represented in the Carnegie Museum.—Rio Parana (Hartman collec- 
tion). One specimen. In pond along banks of Rio Negro, Santa Isabel, Uruguay 
(J. D. Haseman coll., February 11, 1909). One specimen. Arroyo Miguelete, 
Montevideo, Uruguay (J. D. Haseman coll., February 17, 1909). One specimen. 
Rio de la Plata, San Isidro, 20 km. N. of Buenos Aires, Argentina (A. Windhausen 
coll., January, 1917). Twenty specimens with soft parts, males and females. 

Distribution. 
Parana to the province of Corrientes in Argentina; also in the Rio Uruguay and the 
Rio Negro, and the tributaries of the La Plata in the Banda Oriental of Uruguay. 

Characters of the Shell—Shell rather large (length up to 100 mm. and over), 
rather thick and solid. Outline very oblique, subovate, longer or shorter, height 
60 to 74 pr. et. of the length. Young shells probably higher and more subrotund, 
according to the growth lines in older shells, but such shells have not been observed 
(the smallest shell is 75 mm. long). Valves not gaping. Dorsal margin straight 


La Plata system, from the mouth near Buenos Aires up the 


or gently curved, generally with a well marked, blunt posterior angle, while the 
anterior angle is less distinct, often quite rounded. Posterior margin obliquely 
descending, generally almost straight, rarely gently convex, and very rarely a 
little concave, curving broadly and regularly into the posterior lower margin, 
generally forming no angle or posterior point, but sometimes with a trace of it- 
The anterior part of the ventral margin is strongly ascending and always more or 
less gently curved, and often almost straight, curving up into the anterior margin, 
which is narrowly rounded. Thus the anterior end of the shell appears much nar- 
rower than the broadly rounded posterior part, rendering the shell decidedly oblique. 

Valves moderately swollen, diameter 38 to 44 pr. ct. of length, rarely slightly 
less. Beaks slightly convex, and only little elevated above the hinge-line, located 
at 28 to 34 pr. ct. of the length. Disk moderately convex, more strongly so over 
the middle part and the posterior ridge; posteriorly compressed. Posterior ridge 
very indistinct, but often there is a radial rib upon the posterior slope, sometimes 
accompanied by a furrow. The anterior end of the shell is also slightly compressed. 

Epidermis rather smooth, but with fine, irregular, concentric strie, almost 
effaced in the middle of the disk and toward the beaks, more distinct toward the 
margins, where they may become sublamellar. Very fine radial, oblique, or 
reticulated wrinkles may be present between the strive. Scalariform radial stripes 
are generally absent, but in some specimens slight traces of them are seen. Color 
of epidermis dark greenish-olive to various shades of brown. Generally there is 


614 MEMOIRS OF THE CARNEGIE MUSEUM. 


more green toward the beaks, more brown toward the margins, but the green 
may extend over nearly the whole shell, or may be absent. Upon the posterior 
slope there may be a few indistinct, dark green rays, and the green color near 
the beaks often has a mottled character, consisting of irregular, darker and lighter 
concentric bands, and, rarely, of indistinet radial rays or blotches. In some 
specimens, the anterior and posterior parts of the shell are different in shade, the 
posterior being darker (more greenish), the two shades being separated rather 
sharply by a radial line. Growth-rests few, and rarely distinct. 

Hinge-line nearly straight, or very gently curved behind the beaks. In front 
of them it descends more or less distinetly, and may ascend again at the anterior 
extremity, thus becoming slightly sinuate. Ligamental sinus triangular, some- 
what variable, but generally deeper than wide, chiefly in older shells, its anterior 
margin mostly vertical to the hinge-line, and its lower point curved more or less 
forward. Often the anterior margin has an S-shaped curve. 

Cavity of shell and beaks moderate. Nacre whitish, iridescent, but none of 
my specimens has red tints. Radial striations are present, but indistinct in older 
shells. Prismatic border broad, unequal in width, broadest along the ascending 
anterior lower margin, narrower in front, and narrowing rather suddenly at the 
beginning of the posterior part of the lower margin. — Its color is grayish or yellowish 
green, or grayish or yellowish white. Anterior adductor-sear well impressed, 
subelliptical, united above with that of the retractor, or sometimes incompletely 
separated. Anterior protractor-sear generally well separated from the adductor- 
sear. Posterior adductor-sear less impressed, subovate, with an upper triangular 
projection formed by the posterior retractor-sear. Pallial line distinet, subecon- 
centric with the shell-margin, and thus more closely approaching the prismatic 
border in the anterior part of the lower margin than before and behind it. No 


dorsal sears. 
MEASUREMENTS. 


Beaks. 


Locality. No. | Sex. Length. Height. Diameter, 

San Isidro...... 19 | ou 75 mm.53) mm.=71 pr. ct. of L.'30 mm. =40 pr. et. of L.| at 25 mm. =33 pr. ct. of L. 
Do. ereate 14 fo) 87 =a 100: “ =64 oe 38 ee ie | 29) “ =33 HY 
Do. St apvste 10 | 2 89 AT aay OS =F) ~ 39 “ =44 1 20)  =29 at 
DOte Wiecoee 2 ||) 39 91 nO =74 re 36.5 =40 = PY Mee 80) 
Do. SOO e PA |) 593 93.5. ** 56 =60 39 =42 26; 7 =28 “a 
Do. ents 8 | oc 103 66.5 =65 37 =36 31 ‘** =30 “ 

Montevideo... ? 77 Seto ae OG: oy 30 “—o—39 ng | 26 “ =34 of 

Santa Isabel... .. 2 95 ae) | =) -=68 a 42 AS =43 = | 33“ =34 = 

Previous MEASUREMENTS. 

D’Orbigny (membranacea).... 90 ie =(3} fA | S583) os 

Simpson (patagonica)........ 81 * 159 “=e se 32 40) ee 

TDO;- "pa eset os. ae 87 saa lOts * -=66 ‘ \37 =A 5 

Simpson (crassa)............ 80 “ee Ow, “= 65 os \32 eh) 

Simpson (wymani)..........) 80 12 VN) ~ =63 Ue 30 So ie 

Lea (figure of wymani).......| 87 Sem ESEy UP 8) ‘ 133 “«  =88 & 


ORTMANN: SOUTH AMERICAN NAIADES. 615 


All of these previous measurements fall within the range of variation of my 
series, with the exception of the diameter given by D’Orbigny, which is somewhat 
lower (33 pr. ct.) than any of my figures (lowest 36 pr. ct.). 

Remarks.—This species is very variable in shape, being sometimes higher, 
sometimes more elongated. There is no indication that the shape is connected 
with sex. Since no very young specimens are at hand, and never have been ob- 
served, we do not positively know anything about their shape, but from the growth- 
lines of the old specimens it is seen that the young shell generally must have been 
comparatively higher: the shell grows, with advancing age, more in the direction 
of the posterior end, so that the longitudinal diameter increases more than the 
vertical. 

There is no doubt in my mind that A. crassa and wymani belong here, and that 
they represent specimens which are a little more elongated than the average; but 
among the set from San Isidro, I have specimens which represent even greater ex- 
tremes than these. 

A. patagonica is rather thick and solid, but varies also in this respect. The 
specimen from Montevideo at hand is not quite as thick as the others, but agrees 
with them in other respects, being also rather elongated. Just such specimens 
induce me to regard the next form (rubicunda) as a variety of patagonica. 

Anatomy.—Soft parts of eight males, one barren, and eleven gravid females 
have been investigated. The breeding season is January. 

The anatomy of latomarginata and wymani has been previously described by 
Lea (Obs. X, 1863, pp. 391, 394) as far as the superficial characters of the gills, 
the palpi, and the branchial and anal openings are concerned. 

Von Ihering (1891, p. 480) describes the eggs and lasidia of Glabaris wymani, 
the former being 0.09 mm. in diameter, the latter 0.086 mm. long. However, since 
he says that his specimens are from Rio Camaquam, I am not sure that they have 
been properly identified. They might belong to A. iheringi (Clessin). 

Anal opening entirely open, separated from the branchial by a connection of 
the mantle-margins. Inner edge of anal smooth above, very finely crenulated 
near the lower end. Branchial opening with small papillze. Palpi nearly semi- 
circular, longer than high, behind abruptly truncated, the posterior margins con- 
nected at base. 

Gills rather wide, the inner much wider than the outer in front, its anterior 
end immediately behind the palpi, and attached along the whole space between 
the palpi and the anterior end of the outer gill. Inner lamina of inner gill entirely 
connected with abdominal sac. Septa of the gills well developed. In the non- 


616 MEMOIRS OF THE CARNEGIE MUSEUM. 


marsupial gills they are irregularly alternating. In the female, the inner gill is 
marsupial nearly throughout its whole length. The septa are stronger and equal, 
having near the outer lamina a swelling indicating ridges projecting into the lumen 
of the water-tubes. When charged the egg-masses occupy only the inner com- 
partments, forming ovisacs, which are somewhat distended, while the outer com- 
partments do not change, and apparently serve-as (secondary) water-tubes. Eggs 
very small. I did not see any larvee. Even in a specimen which had the gills 
only partially charged (anteriorly), and which might have been discharging, the 
eggs consisted only of a globular mass of cells enclosed in a membrance. 


57a. ANODONTITES PATAGONICA RUBICUNDA (Lea) (1860). 
Diagram of soft parts: Text-fig. 8, p. 458. 
Section of gills: Plate XLVIII, fig. 8. 
Anodonta rubicunda Lea, Obs. X, 1863, Pl. 46, fig. 299; Corsi, 1901, p. 455. 
Anodonta pazii Lea (1866) Obs. XII, 1869, Pl. 36, fig. 87. 
Anodon rubicundus SowerBy, XVII, 1870, Pl. 30, fig. 118. 
Glabaris rubicunda Pitssry & Rusu, 1896, p. 81; Smupson, 1900, p. 913. 
Glabaris latomarginatus felix PrusBry, 1896, p. 563, Pl. 26, fig. 8. 
Glabaris pazii SIMPSON, 1900, p. 918. 
Anodontites latomarginata felix Simpson, 1914, p. 1405. 
Anodontites pazi Simpson, 1914, p. 1408; Haas, 1916, pp. 30, 55. 
Anodontites rubicundus Simpson, 1914, p. 1409. 

Type-locality.— Uruguay River. 

Other Localities.—Rio de la Plata, Colonia, Uruguay (Pilsbry & Rush, rubi- 
cunda) (Pilsbry, felix); Uruguay River, Paysandu, Uruguay (Pilsbry & Rush); 
Uruguay River, Salto Oriental, Uruguay (Haas). 

New Localities —Rio Uruguay (in mud), Uruguayana, Rio Grande do Sul, 
Brazil (J. D. Haseman, February 5, 1909). Twelve specimens, eleven of them 
with soft parts, males and females. In pond along banks of Rio Negro, Santa 
Isabel, Uruguay (J. D. Haseman coll., February 11, 1909). Three specimens. 
Rio Ibicuhy, Cacequy, Rio Grande do Sul, Brazil (J. D. Haseman coll., February 
1, 1909). One male with soft parts. Rio Cacequy (in sand), Cacequy, Rio Grande 
do Sul, Brazil (J. D. Haseman coll., February 2, 1909). One female with soft 
parts. 

Distribution.—Known only from the Uruguay and the Rio de la Plata below 
the mouth of the Uruguay, and from the Rio Negro in Uruguay and Rios Ibicuhy 
and Cacequy in Rio Grande do Sul, these being tributaries of the Uruguay. 


ORTMANN: SOUTH AMERICAN NAIADES. 617 


Closely allied to A. patagonica, but differing in being somewhat smaller (maxi- 
mum length 84 mm.), with a thinner shell. The outline of the shell is more nearly 
and more frequently subrotund, and the diameter ranges higher (up to 50 pr. ct.). 
The nacre very often, but not always, has reddish or purple tints. 


MEASUREMENTS (SPECIMENS FROM URUGUAYANA). 


No. | Sex. Length. Height. | Diameter Beaks. 
1 erence | ou | 47.5 mm. 36.5 mm. =77 pr. ct. of L.| 19.5 mm. =41 pr. ct. of L. at 17 mm. =36pr.ct.of L. 
Di. 2 9 | 53 seyaaep - “° <= 84 < | 24.5 °S =46 ve 19) sh ma 
rT. fo) WOON Renae. =i z | 3220 . eae 3y m Wa 0 oo - 
Ce i) 62 "150 “ =81 * | 31 =50 24 “  =39 ca 
oe oi GGuen ton = " Wey =41 22 =33 “ 
ase t Q i ONE 7 i J isa steels 22.5 “ =30 
Acne 9 | 84 oon 8 =70 | 35 ‘42 29 =30 ; 
OLDER MEASUREMENTS. 
Simpson, See 59 men loL So 30 “ =51 ; (Type) 
Do. 77 el To) 36 “  =48 7 
Simpson, pazi..... 60 oe 4a: Seti 26 oa i (Type) 
Do. Se xellioe “138 St i 26 “" =49 My 
Pilsbry, feliz...... 49 coat 0) So e=7il : 18 oi as 
Do. Seders aloo tots) Si) 20.5 =39 ‘ 


Remarks.—All the previous measurements fall within the range of variation of 
my specimens, only the type of Lea’s rubicunda is higher, shorter, and more swollen 
than any of my specimens. Thus we are to regard the type of rubicunda as an 
exceptional specimen, which is also peculiar in the fact that the posterior margin 
forms nearly a right angle with the upper margin. All these peculiar features are 
correlated, however. The normal type of this form is better represented by Lea’s 
pazi; yet there are specimen in my material which distinctly approach the rubicunda- 
type. 

It is unknown whether this form ever reaches the size of A. patagonica, and 
in the absence of young specimens of the latter it is impossible to compare them 
directly. But it seems that the more nearly rotund shape is rather a juvenile 
character, although there are young specimens in my material which are more 
elongated. From the measurements given it is seen that the height ranges from 
70 to 84 pr. ct. in my material, reaching 86 pr. ct. in Lea’s type of rubicunda, while 
it ranges from 60 to 74 pr. et. in patagonica. The diameter in rubicunda is from 37 
to 50 pr. et. (51 pr. et. in the type), while in patagonica it is from 36 to 44 pr. ct. 

Clearly height and diameter are correlated, a shorter and higher shell being 
also more swollen than a more elongate one. The slight difference in the location 
of the beaks (30 to 39 pr. et. in rubicunda, 28 to 34 pr. ct. in patagonica) is also 
connected with this. Finally it may be that all these differences in the shape are 
connected with age, and this may be true also of the thickness of the shell. How- 


618 MEMOIRS OF THE CARNEGIE MUSEUM. 


ever, my largest specimens of rubicunda differ in this from the smallest specimens 
of patagonica (of about the same size), but not very strikingly. 

Much stress has been laid in the original descriptions of A. rubicunda and 
pazi upon the red color of the nacre. According to my material this is extremely 
variable. In some specimens the color does not differ from that of A. patagonica, 
being whitish. In others it is more or less tinted with red or purple, and then also, 
generally, the prismatic border is dull purplish gray. But this also is not a constant 
character. 

Pilsbry’s felix is said to be characterized by its light, yellow-green epidermis, 
which has radiating or irregularly zig-zag lines of green. I see traces of this in 
some of my specimens from Uruguayana and Santa Isabel, and there are also here 
and there black markings on the inside along the pallial line and near the muscle- 
sears (and elsewhere), mentioned by Pilsbry as occurring in felix. These are in- 
dividual characters. 

The epidermis of rubicunda is much as in patagonica, 7.e., somewhat lamellar 
near the margins, smoother in the middle. Scalariform stripes are sometimes 
indicated, but are mostly absent. The color in younger specimens 1s generally dark 
green all over the shell, but a few are brownish. Those with intense red tints 
on the inside are sometimes a little reddish brown on the outside. The largest 
specimen in the color of the epidermis is much like patagonica, brownish, inclining 
to olive toward the beaks. 

D’Orbigny says of patagonica (membranacea) that it is very variable; that it 
is larger and thicker in the larger rivers; more elongated in lakes; and that it be- 
comes reddish on the inside in small rivers. My specimens support the latter 
observation, for they all are, so far as they may be ealled rubicunda and have red 
nacre, from comparatively small rivers (Rio Negro, upper Uruguay, Ibicuhy, and 
Cacequy). But, of course, this requires further study and more material. 

Anatomy: The soft parts of six males and seven females are at hand, one of the 
latter gravid (February 5). 

The anatomy of two males of pazi has been described by Lea, but only the 
major features have been mentioned. According to my material the soft parts 
agree entirely with those of the typical patagonica. In the gravid female the 
swelling of the charged marsupium is not considerable. The small eggs hang 
loosely together, and easily fall apart. No fully developed larvee could be found. 
A diagrammatic figure of the soft parts is given in text-figure 3 (p. 458), and the 
structure of the gills of a barren female in cross-section is shown on Pl. XLVIII, 
fig. 8. 


ORTMANN: SOUTH AMERICAN NAIADES. 619 


58. ANODONTITES PUELCHANA (D’Orbigny) (1835). 


- 


Anodonta puelchana D’OrsiGNyY, 1843, p. 620, Pl. 79, figs. 7-9. 
Glabaris puelchanus Simpson, 1900, p. 921. 
Anodontites puelchanus Piuspry, 1911, p. 609. 

Simpson (1914, p. 1420) unites this with A. limnoica D’Orbigny, but the latter 
has a very narrow prismatic border. According to my observations, the width 
of this border is a very constant and important character. Simpson places this 
species in the group of crispata; but there is not the slightest trace of the character- 
istic sculpture of the epidermis of this group. That Simpson has entirely mis- 
understood this species is shown by the fact that he unites A. obtusula Hupé with 
it. The latter is a species which is not at all oblique. 

Ty pe-locality—Marsh of San Xavier on Rio Negro, above Carmen de Pata- 
gones, Argentina. 

Additional Locality —Twelve leagues from Chichinal, Patagonia (on Rio Negro) 
(Pilsbry). 

New Locality.—Rio Limay, Patagonia (drainage of Rio Negro) (W. Israél 
donor). Two specimens with soft parts, male and female. 

Distribution.—Known only.from the Rio Negro-drainage in Patagonia. Von 
Thering (1893, p. 118) lists it as from the lower Parana, but without substantiating 
this record. 

According to D’Orbigny’s description and figure, this species is an obliquely- 
ovate, much compressed, thin shell, with shining epidermis, and wide prismatic 
border. It is surely related to patagonica, being, however, not so high and more 
elongated (height 57 to 65 pr. ct. of length, while patagonica has the height 60 to 
84 pr. ct. The diameter is about 31 pr. ct. while in patagonica it never falls below 
33 pr. ct. and only rarely below 40 pr. ct. 

The two specimens before me have the wide prismatic border, somewhat 
unequal in width; the nacre is whitish with pinkish shades (D’Orbigny says “ blane- 
rose”). The epidermis is highly polished and shining; there are some concentric 
grooves, but the fine concentric strie are missing upon the greater part of the disk, 
and are only slightly developed near the margins. There are, chiefly in my larger 
specimen, a few sealariform stripes upon the anterior part of the shell, consisting 
of radial bands of short, concentric wrinkles. Upon the posterior slope there is 
an indication of a radial rib. Color of epidermis greenish brown, more greenish 
toward the beaks, more brownish toward the margins, with very indistinct traces 
of green rays upon the posterior slope. 


620 MEMOIRS OF THE CARNEGIE MUSEUM. 


M&rASUREMENTS. 


No. | Sex. | Length. Height. Diameter. | Beaks. 
veo o | 40 mm. | 26 mm.=65 pr. ct. of L. | 12.5 mm. =381 pr. ct. of L.lat 13.5 mm. =34 pr. ct. of L. 
reli tom |More 2 Wey Use Gy, - 20, = 311 a 21 “ =32 ae 


D’Orbigny .| 60“ —5\// i =3l - 


Anatomy.—The soft parts of the male and female at hand are not in good con- 
dition, the female being the better of the two. The usual structure of the genus, 
however, could be made out, and no special features require mention. 


59. ANODONTITES IHERINGI (Clessin) (1882). 

Shells: Plate XLII, fig. 8; Plate XLIII, fig. 1; Plate XLIV, fig. 1. 
Anodonta theringi CLesstn, Malakazo6l. Blett., V, 1882, p. 191, PL. 4, fig. 5. 
Glabaris theringi Stmpson, 1900, p. 919. 

Anodontites sirionos theringi Stupson, 1914, p- 1408. 

Type-locality.—Taguara del Mundo Novo, Rio Grande do Sul, Brazil (system 
of Rio Guahyba, N. E. of Porto Alegre). 

New Localities—Rio Jacuhy, Cachoeira, Rio Grande do Sul, Brazil (J. D. 
Haseman coll., January 26, 1909). One young specimen, with soft parts, sex not 
determined. Rio Vaccahy-Mirim, Santa Maria, Rio Grande do Sul, Brazil (J. 
D. Haseman coll., January 29, 1909). Three specimens, with soft parts, two males 
and a female. 

Distribution.—Guahyba-drainage in Rio Grande do Sul. 

This species very closely resembles A. patagonica, but is more elongated and 
oblique, so that in outline it is still more like A. puelchana. To the latter species 
it is related also in the more compressed shell. 

The shell is rather thin, of medium size. The outline is obliquely ovate, 
narrower anteriorly, broader (higher) posteriorly. The lower margin ascends in 
its anterior portion, and may be gently curved or nearly straight. Valves gently 
convex, rather compressed. The prismatic border is not so wide as in patagonica 
and puelchana, but it is of the same general character, being wider along the an- 
terior lower margin. It is of a grayish green color. The nacre is silvery white, 
highly iridescent, often greenish or grayish discolored. Ligamental sinus about 
as deep as wide, its anterior margin vertical, with the point bending forward. 

The chief difference from patagonica, and especially from puelchana, is in 
the texture and color of the epidermis. The latter is brownish or brownish olive, 
not very shining, covered with close, subeoncentric strive, sublamellar near the 
margins. Scalariform stripes are distinct upon the anterior half of the shell, 


ORTMANN: SOUTH AMERICAN NAIADES. 621 


consisting of radial bands of short, subconcentric wrinkles. These stripes may 
also be seen upon the posterior section of the shell, but less frequently and less 
distinctly. 


MEASUREMENTS. 


Location. | z Length. Height Diameter. i Beaks Figured 


Cachoeira...| | ? (22.5 mm. 14.5mm. =64 pr.ct. of L.! 8 mm. =35 pr. ct. of L. at 6.5 mm. =29 pr. ct. of L. 

Santa Maria.) 1 07 53 Sapo wey ip OD He 18 “ =34 r 17 ae Pl. XLII, fig. 8 
Do. .| 210756 SOG: ee | —Oo > 20) > = 50 - 18 =32 Pl. XLII, fig. 1 
Do. 3 =31 Pl 


|3|9\69 “(43 “ =62 a 25 “ =36 + 21.5 


.| . XLIV, fig. 1. 


Simpson’s measurements are: Length 61 mm.; Height 39 mm. = 64 pr. ct. of L.; 
Diameter 22 mm. = 36 pr. ct. of Length. 

Remarks.—The original description and that given by Simpson are scarcely 
sufficient to enable the species to be recognized, but none of the characters given 
conflict with those exhibited by my specimens, and the measurements apply very 
well. Since the original A. iheringi comes also from the same river-system (Guahy- 
ba) as-:my specimens, I have no doubt that we are dealing with this species. 

Anatomy.—Two males, and one female are at hand for study. 

The soft parts are absolutely identical with those of A. patagonica. 


6. Group or Anodontites trapesialis. 

Shell strongly oblique, subovate to subtrapezoidal, narrowly rounded, or 
bluntly pointed behind. Epidermis shining, only here and there, and not always, 
with sealariform radial bands of wrinkles. Prismatic border narrow and of equal 
width. 

A rather well defined group, distinguished also by the large and comparatively 
thin shell: the largest species of the genus belong here. Usually we discover that 
the valves are gaping anteriorly, and sometimes also posteriorly. Whether this 
is connected with the anatomical structure, or with habits, is not known. There 
is hardly a question that the genus Leila is descended from forms belonging to this 
group. % 

Von Ihering has given a partial key to the species (1890, p. 157), which I 
have used to great advantage. But great difficulties arise in distinguishing the 
species, and young individuals are often very hard to correlate with older ones. 
Although I possess good material representing this group, it includes only com- 
paratively few forms, so that Iam unable to forma definite opinion as to those which 
are not represented. I treat my specimens here under the names to which they 
seem to belong, without going into detail as to their affinities and relationships. 


622 MEMOIRS OF THE CARNEGIE MUSEUM. 


60a. ANODONTITES TRAPESIALIS ANSERINA (Spix) (1827). 
Simpson, 1914, p. 1430. 

New Locality.—Rio Paraguay, Corumba, Matto Grosso, Brazil (H. H. Smith 
coll.). Three right valves. 

I do not propose to go into a lengthy discussion of this form. I merely desire 
to say that two of my specimens agree very well in shape and size, with the figures 
given by Spix, while the third more resembles Sowerby’s figure (Pl. 31, fig. 125). 
They vary slightly among themselves in the degree of the taper of the anterior 
end. In all of them the hinge-line is very gently curved, but not sinuous (as in 
A. exotica). 

The original A. anserina is from the Rio Solimoes, in the province of Amazonas. 


60b. ANODONTITES TRAPESIALIS SCRIPTA (Sowerby) (1867). 
Simpson, 1914, p. 1480. 

Simpson unites with this A. bahiensis Kuester (Von Ihering, 1890, pp. 153, 
157; 1893, p. 115; 1910, p. 138). 

No exact localities are known. A. bahiensis, which is oiven from Bahia, is 
not from that region, but, according to Von Ihering (1910) from the upper Amazon 
and Ecuador. Von Ihering (1890, p. 152) thinks, on the other hand, that scripta 
is identical with exotica. 

New Locality.—Rio Ribeira, Iguapé, Sao Paulo, Brazil (Haseman collection, 
collected by Richardo Krone). Two odd valves, right and left. 

My specimens agree well with Sowerby’s (Pl. 4, fig. 9) in shape and size. One 
of them has the characteristic zig-zag black markings on the inside, while in the 
other one these are found only near the posterior adductor-scar. However, the 
color of the epidermis in both is not brownish, but green, darker upon the posterior 
slope. Very obscure green rays are seen on some parts of the disk. Since Simpson 
says that the color of the epidermis varies to the “ordinary” (green) color, I do 
not think that this prevents the union of our specimens with scripta. My left 
valve has anteriorly two short scalariform stripes, barely visible; in the right valve 
such are entirely absent. 


MB®ASUREMENTS. 


| Length. Height. Diameter. | Beaks. 
= | 
Lefticcrstien 154 mm. 93 mm.=60 pr. et. of L. | 50 mm.=32 pr. et. of L. | at 61 mm.=40 pr. et. of L. 
Right aoe | 160 re 96 eo) Zs (Asie 30 a | 60 “ =88 “ 


ORTMANN: SOUTH AMERICAN NAIADES. 623 


61. ANODONTITES MORICANDI (Lea) (1860). 
Simpson, 1914, p. 1439. 

Synonym: 

Anodonta hertwigi Von InERtNG, 1890, p. 150, Pl. 9, fig. 7; 1910, p. 138. 

Von Thering (1910, p. 138) regards Anodon radiatus Spix (1827) as the young 
of this species, and in that case, of course, the specific name radiata should supersede 
that of moricandi. However, I am not convinced that this is right, for those of 
our specimens which are nearly of the size of Spix’ original, do not agree with it 
in shape. They do not have the strongly convex lower margin, and the relative 
dimensions, chiefly the height, also do not fit. According to Von Ihering, the 
measurements of radiata are: Length 70 mm.; Height 36 mm. = 51 pr. et. of L.: 
Diameter 20 mm. = 29 pr. ct. L. 

Type-locality— Bahia, Brazil. 

Other Localities.—Rio Sao Francisco, Villa Nova, Sergipe, Brazil (Von Ther- 
ing); Rio Paraguasst, Bahia, Brazil (Von Ihering); Rio Pardo, Bahia, Brazil (Von 
Ihering). 

New Locality—In a lagoon of Rio Parahyba, Campos, Rio de Janeiro, Brazil 
(J. D. Haseman coll., June 14, 1908). Six specimens. 

Distribution.—Streams of eastern Brazil, from mouth of Rio Sio Francisco in 
Sergipe southward to Rio Parahyba in Rio de Janeiro. Known from the rivers 
Sao Francisco, Paraguasst, Pardo, and Parahyba. 

My specimens agree well with this species. What is regarded as one of its 
essential characters, the flattening of the disk on the sides, is developed only in 
larger specimens. My largest specimen shows it distinctly, although not as strik- 
ingly as Lea’s figure. In the smaller ones this is less evident, but even in these 
the greatest diameter of the shell is in about the middle of the length, not much 
behind the beaks. 


MEASUREMENTS. 

Length. Height. | Diameter. Beaks 
30.5 mm.|17 mm.=56 pr. et. of L.| 10 = mm.=32 pr. ct. of L.at 11 mm.=36 pr. et. of L. 
49 Sas 7 of Weouen 50 ss 1S ih sf 
to” NAGS EES — (60 ¢¢ Bo ati 23 a 4 Nae Re 
78 seen ae ee et 7, its Dee) ie Way (OS RR} 
89 Eoin 8 Sai a | 2 ey SPA) se 29 rs 
98 a 57 “ =58 aS | 30 Sail 7 34 S55) 
104 “ |61 ae UL | 32 te 2 30 1 = (Lea’s fig.) 
Dg SO t= '60 = | 35 = = 50 ve (Simpson) 
ATO 25 NiG2, 0) us | less than 34 Us (hertwigi) 


624 MEMOIRS OF THE CARNEGIE MUSEUM. 


62. ANODONTITES RIOGRANDENSIS (Von Ihering) (1890). 
Shells: Plate XLIII, figs. 2, 3; Plate XLIV, fig. 2. 
Anodonta riograndensis VON IHmRING, 1890, pp. 154, 158. 
Glabaris riograndensis VON THERING; 1893, pp. 118, 119. 
Anodonta exotica Corst (non LAMARCK), 1901, p. 456, fig. 37. 

It is quite possible that A. exotica of D’Orbigny (non Lamarck) represents 
chiefly this species. However, on account of the great diameter (44 pr. ct. of length) 
of the specimen measured, this appears to be rather A. forbesiana. Since there is 
no figure given, D’Orbigny’s species remains doubtful. The figure of A. exotica 
given by Corsi certainly in this species. 

Type-locality—Rio Grande do Sul, Brazil. 

Other Localities.—Rio Paraguay (Von Ihering); Lower Paranda and La Plata 
Rivers (Von Ihering); Rio Uruguay (Von Ihering); Department of Colonia, Uruguay 
(Corsi); Arroyo Mendoza, Department Florida, Uruguay (Corsi); Montevideo, 
Uruguay (Von Thering). 

New Localities.—In a pond along banks of the Rio Negro, Santa Isabel, 
Uruguay (J. D. Haseman coll., February 11, 1909). Two males with soft parts, 
four odd right vales. Headwaters of Rio Paraguay, Santa Rita, Matto Grosso, 
Brazil (J. D. Haseman coll., June 12, 1909). One specimen. Rio de la Plata, 
San Isidro, 20 km. N. of Buenos Aires, Argentina (A. Windhausen coll., January 
1917). Three specimens, male, and gravid females, with soft parts. 

Distribution —La Plata-drainage from Buenos Aires up to the headwaters of 
the Paraguay in Matto Grosso; in the Uruguay and its tributaries; and also in 
streams of the Banda Oriental to Florida and Montevideo. According to Von 
Ihering occurring also in the Rio Grande do Sul, but exact localities not known. 

Characters of Shell.—Shell large (length up to 130 mm. and over), moderately 
and variably solid, but never thin. Valves distinetly gaping anteriorly, slightly 
so posteriorly. Outline subtrapezoidal, rather elongated, height 54 to 63 pr. et. 
of the length, distinctly oblique. Upper margin gently curved or nearly straight, 
forming a more or less distinct, obtuse angle with the posterior margin, and also 
with the anterior margin. Sometimes in old specimens these angles are obliterated. 
Posterior margin obliquely descending, not very steep, straight, or gently convex, 
curving around into the posterior lower margin, forming a blunt posterior point 
of the shell, situated a little above the base-line. Lower margin convex, but 
ascending in its anterior part, and becoming here nearly straight for a distance just 
in front of the middle; then curving up into the anterior margin. Thus the shell 
is distinctly narrower anteriorly, and this produces the oblique shape. Often 


a 


ORTMANN: SOUTH AMERICAN NAIADES. 625 


this shape is obscured on an external view on account of the elevation of the beaks. 
but it is best seen from the inside, when the ligament behind the beaks is placed 
horizontally. 


Valves moderately convex, somewhat flattened upon the sides, greatest diam- 
eter 34 to 40 pr. et. of the length, located upon the posterior ridge, some distance 
behind the beaks. Posterior ridge indistinct. Posterior slope compressed, some- 
times with traces of a radial ridge and furrow. Beaks a little inflated and a little 
elevated above the hinge-line, their tips located at 29 to 33 pr. et. of the length. 

Epidermis rather smooth and shining. Irregular subconcentric ridges are 
present, but no lamelliform strize, except on the posterior slope, where they may 
be more or less distinct, and rather crowded. Upon the smooth part of the disk 
there are often a few radial scalariform stripes, consisting of short subconcentrie 
wrinkles. But these may be entirely missing. Color of epidermis prevailingly 
green, but shading into brown, often with concentric bands of darker or lighter 
green and brown. Green rays may be present or absent; when present, they are 
best developed on and just in front of the posterior ridge. Posterior slope generally 
dark green to blackish, often with a few black rays. 

Hinge-line nearly straight behind the beaks, but gently and distinctly curving 
down anteriorly, so that the whole hinge-line appears as gently curved. A trace 
of a slight sinuation may be observed in a very obseure elevation of the hinge- 
line at its anterior end, but generally this is not the case. Ligamental sinus broad 
and deep, in older specimens deeper than in younger ones, its anterior margin 
running obliquely backward in young individuals, but being vertical in old ones. 
Sometimes the anterior margin is curved, the lower point turning forwards. 

Cavity of shell and beaks moderate, corresponding to the obesity of the shell. 
Nacre whitish and iridescent, often much discolored, and quite frequently there 
are fine, irregular, subconcentric, waved, or zig-zag, black lines inside of the shell, 
chiefly near the pallial line. Faint radial striations may be present in young 
specimens. Prismatic border narrow or very narrow, subequal in width, grayish 
green or brownish green. 

Anterior adductor-sear slightly impressed, irregular in outline, with an upper 
process representing the anterior retractor-sear. Anterior protractor-sear separated 
from adductor-scar. Posterior adductor-sear faint and often indistinct, the pos- 
terior retractor forming an upper triangular process thereof. No dorsal scars. 
Pallial line subconcentric to the margin. 

Remarks.—The height is given by Von Ihering as from 49 to 57 pr. et. of length, 
thus being less on the average than in my specimens; but I think this is due to the 


626 MEMOIRS OF THE CARNEGIE MUSEUM. 


fact that Von Ihering did not measure in the way I did (See p. 526). If I measure 
the length of my specimens along the longest axis (diagonally), and the height 
vertically to it, I obtain for the above specimens figures more nearly agreeing with 
those of Von Ihering from 51 to 59 pr. et. of length. 


MEASUREMENTS. 


| 
3 Length. Height. Diameter. Beaks. Figured. 


Localities 


Santa Isabel . 


3/?) 95 mm.|/59.5mm. =63 pr.ct. of L.'32 mm. =34 pr. ct. of L.|at 28 mm. =29 pr. ct. of L. 


Do. .| 4] ? |102 55 OSS = 54 38) = 87 29:5 “* =29 
Do. alotLO%)  |Oai05 s8 =59 st 43 “* =40 te 365 5 —30 ts 

San Isidro. |y ONS oe eo | Ae OO) - 48 “ =39 ef 3{3) pts) us Pl XL, f. 2: 
Do. CNioHiPaHa LON 2 = Gil “s 49. “* =A0 36 “ =29 “ Pl) Xa he 
Do. ie OSE “ONSGe So =68 “f 5a AO) ee 45, SE =33 us | Pl. XLT, £22! 


In other respects, the characters given by Yon Ihering for riograndensis agree 
with my specimens. This is especially true of the diameter, which, according 
to Von Ihering ranges from 30 to 39 pr. ct., and in my specimens from 34 to 40 pr. ct. 
Von Ihering believes that the diameter as well as the height differ according to 
sex. According to my material there surely is no such differentiation. It is im- 
possible to directly compare my measurements for the location of the beaks (29 
to 33 pr. et.) with those given by Von Ihering, because he measured the distance 
from the anterior end of the hinge-line (34 to 48 pr. et.); but I should say that 
measurements of my specimens taken in the same way give, for the above speci- 
mens, the values: 36, 35, 37, 43, 40, 44 pr. et. of length, agreeing fully with Von 
Thering’s. 

The point of the beaks is inclined forwards, as Von Ihering mentions, but 
not too much stress should be laid upon this character. An important feature, 
however, is the curved hinge-line. 

Glabaris trapesialis cygneiformis Pilsbry (1896, p. 563, Pl. 26, figs. 4, 5) from 
Maldonado, Uruguay, surely is closely allied. But, as Pilsbry points out, it is 
more compressed than riograndensis (Diam. only 26 pr. et.), and its posterior end 
is more elevated above the base-line; it is thus less oblique. For this reason I 
cannot unite it with the present species, although it may fall under it. 

Glabaris simpsonianus Pilsbry (ibid., p. 564, Pl. 27, fig. 13) from Rio de la 
Plata, is also very much like riograndensis. The height of 56 pr. ct. and the diam- ~ 
eter of 38 pr. et. fall within the range of variation of riograndensis. But it is said 
to be a very solid shell, of a rather regular, oblong-oval shape, with a large, elongated 
anterior protractor scar. Having no specimens corresponding to it, | cannot express 
an opinion. 

Anatomy.—The soft parts of three males and two gravid females are at hand, 


——T 


ORTMANN: SOUTH AMERICAN NATADES. 627 


the latter collected in January. Von Ihering found gravid females with lasidia on 
May 28. 

Anal opening entirely open, its inner edge smooth, separated from the branchial 
opening by a mantle-connection. Branchial opening with fine papille on imner 
edge. Palpi very large, nearly semicircular, lower margins rounded, posteriorly 
truncated, without a posterior point. Posterior margins widely separated at 
base (this is a peculiar feature, not observed in any of the foregoing species). 

Gills long and wide, the inner the wider anteriorly, its anterior end inserted 
between the posterior ends of the palpi (this is also a peculiar feature). Outer 
gill with the anterior end at the highest point of the mantle-attachment-line. Inner 
lamina of inner gill entirely connected with abdominal sac. Gills with well de- 
veloped septa running in the direction of the gill-filaments, alternately (but ir- 
regularly so) stronger and weaker in the non-marsupial gills. The inner gill of 
the female is marsupial, with stronger, more uniform septa, which, however, are 
not more closely set, and have the usual vertical ridges near the outer lamina, 
projecting into the lumen of the water-tubes. When charged, only the inner com- 
partment is filled with ova, thus becoming an ovisac, while the outer compartment 
remains a (secondary) water-tube. Egg-masses only loosely hanging together. 
Eggs very small, according to Von Ihering 0.071 to 0.090 mm. in diameter, while 
I have found them to be about 0.08 mm. In this species also I have not been able 
to find mature larve, but this is one of the species, in which Von Thering has ob- 
served the lasidium, which he describes as being 0.1 mm. long. 


63. ANODONTITES FORBESIANA (LEA) (1860). 
Shells: Plate XLIII, fig. 4; Plate XLIV, fig. 3. 
Simpson, 1914, p. 1488. 

Additional References.—Anodonta forbesiana Von TnHErRING, 1890, p. 158. 
Corst, 1901, p. 457. 

Glabaris forbesianus Pinspry & Rus#; 1896, p. 81. 

Type-locality Uruguay River. : 

Other Localities.—Rio de la Plata, Colonia, Uruguay (Pilsbry & Rush). 

New Localities—Rio Uruguay (in mud), Uruguayana, Rio Grande do Sul, 
Brazil (J. D. Haseman coll., February 5, 1909). Fourteen specimens, males and 
females, all with soft parts. In pond along banks of Rio Negro, Santa Isabel, 
Uruguay (J. D. Haseman coll., February 11, 1909). Two odd right valves. 

Distribution. Known only from the Rio de la Plata below the mouth of the 
Uruguay, Rio Uruguay up to Rio Grande do Sul, and its tributary the Rio Negro. 


628 MEMOIRS OF THE CARNEGIE MUSEUM. 


Simpson also gives Peru, but I do not know on what authority, and strongly doubt 
this record. 

Von Thering (1890) pointed out the differences from A. riograndensis, to 
which this species is closely allied. The original specimens of A. forbesiana were 
injured at the posterior end, and it was believed that in uninjured ones this end 
might be more strongly produced. However, Lea’s figure shows in the growth- 
lines that the shape of the shell, before it was injured, was similarly truneated, and 
my series, which contains a majority of intact shells, demonstrates that the normal 
shape of this species also exhibits this truncation, 7.e., a steeply descending pos- 
terior margin. This is the chief character of this species, and in consequence, the 
dimensions are different from those of A. riograndensis. 

This difference is seen first of all in the height, which varies from about 60 to 
69 pr. et., falling under 60 pr. ct. only in very young specimens, while in riograndensis 
it is from 54 to 63 pr. et. The diameter of the two species is about the same, but 
slightly higher on the average in forbesiana (35 to 48 pr. ct. and in young ones 
as low as 33 pr. et. against 34 to 40 in riograndensis). The beaks of forbesiana 
are farther removed from the anterior end: 32 to 38 pr. cet., against 29 to 33 
pr. et. in riograndensis. Von Ihering gives the umbonal index as 48 pr. et., but 
this is due to his different method of measuring; measured in my specimens ac- 
cording to his method, it would be from 42 to 56 pr. et., while it is 34 to 48 pr. et. 
in riograndensis. The index above 50 pr. ct. is found only in my youngest speci- 
mens, where the ligamental sinus is very anterior, thus making the hinge-line very 
short. 

Finally, in forbesiana, the hinge-line is practically straight, as mentioned by 
Von Ihering, and represented in Lea’s figure. This holds good in all of my speci- 
mens. 

In other respects this species agrees with riograndensis, but it should be re- 
marked that the radial sealariform stripes are generally absent or very poorly 
developed; only in one or two eases a few of them are distinctly seen on the anterior 


part of the shell. 
MEASUREMENTS (SPECIMENS FROM URUGUAYANA). 


No Sex Length | Height. | Diameter. | Beaks. 

(os J(?)} 29mm. 16 mm. =55 pr.ct. of L. 9.5mm. =33 pr.ct. of L.at 10 mm. =34 pr. et. of L. 

1 o | 49 “ |29 29) “ Ao 30 7m 17 sate oo o 

2. o 71 “ (42:5 “~- =60 ‘ 25 se $ 23 ——_ = 

Ait OF ei enh) Ob 28 “ =39 " 25:D) sa 

Ve 9 85 “ |54.5 “ =64 36 iS 4D 3 29 = sh 

CE e.al| eh 87 “ 159 =68 : 42: So = 48 B38 “= a Pl. XLITI, fig. 4. 
Oe fof 100 * 69 =69 ; 43 « =43 37 c= fs 
11 2 |108 70 =65 ~ AG St = 43 : 38.5 = ty | Pl. XLIV, fig. 3. 


se 
Ls 
e 
= 
= 
| 
= 
ll 
|& 
| 
on 
_ 
Il 
cs 
4 
_— 
_ 
Il 
we 
va 


ae 


-ORTMANN: SOUTH AMERICAN NAIADES. 629 


Simpson’s measurements do not agree with these figures. 

It should be noticed that young specimens are not so high, and also less swollen 
than older individuals, and thus the typical shape is less evident in them. They 
are also extremely thin-shelled, while older ones are rather solid. 

Anatomy.—I have nine males and five females. The structure is exactly like 


that of A. riograndensis. The palpi have their posterior bases separated; for 


about two-thirds of their length the bases are contiguous, but then they diverge. 
The inner gill begins just without and close to the end of the inner palpus. 


64. ANODONTITES RIOPLATENSIS (SOWERBY) (1870). 
Anodon rioplatensis SowERBy, XVII, 1870, Pl. 26, fig. 101. 
Glabaris trapesialis rioplatensis Simpson, 1900, p. 925. 
Anodontites trapesialis rioplatensis Simpson, 1914, p. 1431. 

Type-locality.—Rio de la Plata. 

Other Localities. —Haas (1916, pp. 29, 54) mentions a closely related form from 
Rio Uruguay, Salto Oriental, Uruguay, which may, or may not, be this. 

New Locality —Rio Limay, Patagonia, Argentina (received in exchange from 
W. Israél). One specimen. 

Distribution —The Rio de la Plata and Rio Negro drainages in Argentina. 
Possibly also in Rio Uruguay. 

We may regard this as an exaggerated forbesiana, with the shell higher and 
shorter, and the beaks more central, but in all other respects it is similar. Sowerby 
calls the shell thin, and describes concentric¢ ‘‘wrinkles”’ on the beaks. Our speci- 
men is rather solid, and the wrinkles are nothing but growth-lines. 


MEASUREMENTS. 


Length. | Height. | Diameter. | Beaks. 


108 mm.| 82 mm. =76 pr. ct. of L. | 49.5 mm. =46 pr. et. of L.| at 48 mm.=40 pr. et. of L. (my speci- 
| | men) 
LOGR RAG) eo => eS (Sowerby’s 
| figure) 


Subgenus LAMPROSCAPHA Swainson (1840). 


Lamproscapha Swarnson, Treat. on Malacology, 1840, p. 381. 
Virgula Simpson, 1900, p. 931; 1914, p. 1454. 

Shell greatly elongated, knife-shaped, sharply pointed behind, with a sharp 
posterior ridge. Posterior retractor-scar completely separated from the adductor- 
sear, and remote from it by about one to three times its own diameter. Epidermis 
not shining, covered with very fine concentric (posteriorly) and radial sealari- 
form (anteriorly) wrinkles. 


630 MEMOIRS OF THE CARNEGIE MUSEUM. 


The greatly elongated shape and the posterior retractor-sear are evidently 
correlated characters. This subgenus apparently stands close to the crispata- 
group of Anodontites in the sculpture of the epidermis. 

Swainson introduced Lamproscapha for four species, of which the first (elongata 
Swainson) was doubtfully referred here. The second is ensiformis. If the latter 
is to be separated from Anodontites, Lamproscapha is the oldest available name. 


65. ANODONTITES (LAMPROSCAPHA) ENSIFORMIS (SPIxX) (1827). 


Anodon ensiformis Sprx & WAGNER, 1827, p. 31, Pl. 24, figs. 1,2. Sowrrsy, XVII, 

1867, Pl. 11, fig. 31 (young). 

Anodonta ensiformis D’OrBrany, 1843, p. 618, Pl. 79, fig. 10. Von Inmrina, 1890, 

p. 161. 

Glabaris ensiformis Stimpson, 1900, p. 932. 
Anodontites ensiformis Stmpson, 1914, p. 1455. Haas, 1916, pp. 36, 57. 

Type-locality not given. 

Other Localities—Rio San Miguel (= Rio Itonama), Bolivia (tributary to 
Guaporé) (D’Orbigny); Rio Piray, Santa Cruz de la Sierra, Bolivia (tributary to 
Rio Marmoré, into which the Guaporé flows) (D’Orbigny); Rio Napo, Mazan, 
Peru (Haas). Repeatedly reported from Brazil, but no exact localities given. 

Lea (Obs. XIII, 1874, p. 27) mentions this species as having been found in 
Guyana, in connection with a species from Yuruari River (tributary to Essequibo). 
Simpson (1900, p. 982 and 1914, p. 1456) deseribes a new species (A. falsa) taken 
by Lea for ensiformis, from the same river (Yuruari), “‘a branch of the Ormoco.” 
The Yuruari, however, is a tributary of the Essequibo, but is located chiefly in 
Venezuela, not in Guyana, and does not belong to the Orinoco-system. 

New Locality.—Rio Machupo, San Joaquim, Bolivia (tributary to Rio Itonama 
and Guaporé) (J. D. Haseman coll., September 5, 1909). Four specimens, three 
of them with soft parts. Another specimen is in the Carnegie Museum (from the 
Hartman collection) labeled ‘‘ Brazil.”’ 

Distribution.— Definite localities are so far known only from the upper Amazon 
and Madeira drainages in Peru and Bolivia. 

Characters of the Shell.—Shell moderately thick; outline much elongated, 
knife-like, pointed behind. Height 25 to 33 pr. ct. of the length. Valves not 
gaping. Dorsal and ventral margins practically parallel, except towards the 
posterior end, where the dorsal margin curves in a gentle curve or a very obtuse 
angle into the posterior margin, which descends obliquely and is straight or gently 
concave. At the posterior end the margin curves sharply around to the ventral 


ORTMANN: SOUTH AMERICAN NAIADES. 631 


‘margin, forming a blunt, but distinet point, which is hardly, or very little, elevated 
above the base-line. Lower margin almost straight, but with a more or less distinct 
concavity in the middle. Anteriorly the lower margin curves up into the rounded 
anterior margin. 

Valves very slightly convex, practically flat upon the sides, and, in large 
specimens, even with a shallow depression corresponding to the concavity of the 
lower margin. The posterior ridge is distinet, but rounded, running towards the 
posterior point of the shell. Above this ridge, the shell is somewhat compressed. 
Diameter 14 to 20 pr. ct. of the length. Beaks low, and hardly elevated above 
- the hinge-line, located at 18 to 26 pr. ct. of the length, and proportionally more 
anterior in older specimens; the large specimen, described by D’Orbigny, has 
them at 15 pr. et. of the length. 

Epidermis not smooth, with irregular concentric lines, heaviest upon the pos- 
terior ridge, and with very fine strive, sublamelliform upon the posterior slope and 
towards the margins. Faint radiating lines are present, dividing the fine striz 
into scalariform stripes of crowded, fine wrinkles, visible only in well-preserved 
specimens, and restricted to the anterior part of the shell. Color of epidermis 
greenish or brownish olive, inclining to blackish in old shells, without color-mark- 
ings and without distinct growth-rests. 

Hinge-line straight behind the beaks, slightly descending in front of them. 
Ligamental sinus much wider than deep, its anterior margin oblique to the hinge- 
line, but more nearly vertical in the largest specimen at hand. 

Cavity of shell and beaks very shallow. Nacre, in all of my specimens, whitish, 
but with blueish and purplish iridescence (according to other authors, it is some- 
times coppery), with irregular radiating lines, most distinct towards the margins. 
Prismatic zone rather narrow, and subconcentric with the margin. Anterior ad- 
ductor-scar well impressed, subovate. Anterior retractor-scar distinet, but con- 
nected with that of the adductor-sear. Anterior protractor-scar separated. Pos- 
terior adductor-sear faint, subovate. Posterior retractor-scar separated from the 
latter and rather removed from it, at least by as much as its own width; in old shells 
up to three times its width. 

Remarks.—There can be no mistaking this species, the elongated shape being 
so characteristic, that no other South American form could be taken for it, with 
the possible exception of A. falsa (Simpson) from Venezuela (See above). It 
constitutes with the latter a peculiar group within the genus, but approaches the 
normal Anodontites (of the crispata-type) more than any other. The location 


632 MEMOIRS OF THE CARNEGIE MUSEUM. 
of the posterior retractor-scar is quite unique, but, of course, is connected with 
the elongated shape of the shell. 


MEASUREMENTS. 


Locality No. | Length. | Height | Diameter. Beaks. 

: JOaguiMn asec : 35 mm. | 10 mm. =29 pr. ct. of L. 6 mm. =17 pr. ct. of L. | at 9 mm. =26 pr. ct. of L. 

Do. ae 1 50. Ss | 15: 3) =30 HY | Oe S20 oe 10) =20) e 

Do. Aieariteeete 2 ome 14 “ =25 te gy, = 6 LN | tae — 0) na 

Do. 3 2 ee itp) 8153 = 10° “> =19 | 10" =19 a 
“Brazil’”. . Stats Peer ste bes | 20 “ =26 a UPA lb) ee 4 °° =18 cz 
D’Orbigny 130 | =29 xe =19 “ | =15 ms 
Simpson. .... el 97 1°25 = 26 155 = 15 A | 

TOs ak ree TOG nee 25 . | lye Re ee! os | 


Anatomy.—The soft parts of three specimens are at hand, but their sex is 
not positively known. 

The structure is that of the genus Anodontites, with such modifications as are 
caused by the elongation of the shell. The mantle-connection between anal and 
branchial openings is a little longer than usual, the gills are extremely long and 
narrow, and the part behind the foot, where the two inner laminz of the inner 
gills are connected, is proportionally longer than in any other species. As indicated 
by the scars of the shell, the posterior retractor muscle is considerably removed 
from the adductor. 

Anal opening entirely open. Branchial opening with very small papille. 
Palpi comparatively long, but narrow, lower margins forming a gentle curve. Pos- 
teriorly they are very briefly truncated, forming the posterior margins, which 
are not connected. Structure of gills as usual, with distinct septa. I have not 
been able to positively identify the sex of the three specimens at hand: the con- 
dition of the gills is rather unsatisfactory, they being much torn, so that no sections 
could be made, and from macroscopical examination (and with a lens) no indica- 
tions of a differention of the inner gills could be detected: this, indeed, would indi- 
cate the male sex, but my specimens are too young for one to be sure about this. 
The inner gill, as usual begins immediately behind the palpi, and the inner lamina 
of the inner gill is entirely connected with the abdominal sac. Foot rather long, 
but altogether small; of course, the real shape could not be made out on account of 
the contraction in alcohol. 


Genus Mycrroropa D’Orbigny (1835). 
Simpson, 1914, p. 1457. 
Characterized by very elongated, subtrapezoidal shell, which is widely gaping 
in front. The chief characters, however, are in the soft parts. The foot is ex- 


ORTMANN: SOUTH AMERICAN NAIADES. 633 


tremely elongated and dilated at the end (button-like), and probably is in life 
never entirely withdrawn into the shell (hence the gaping margins). In addition, 
the branchial opening is said to be closed below (Simpson), but I have not been 
able to confirm this, and furthermore the pallial line does not show any indication 
of this (having no sinus). D’Orbigny makes the positive statement that the bran- 
chial is not closed. The anal opening is closed in part. 

This genus has a wide distribution in South America, from the Cordilleras 
eastward, and from Argentina northwards into Central America, at least as far 
as Guatemala. : 

Von Ihering has given a key for the species (1910, p. 118); although this is 
not always quite satisfactory, I have used it in the identification of my compara- 
tively meagre material. Von Ihering’s treatment of the genus surely has cleared 
up a good deal, but it is not to be regarded as final. His opinion that there are 
species of this genus in Eastern Asia (Solenaia) certainly is incorrect. We do not 
know the anatomical structure of the latter, except that the foot is said to be 
similarly developed. But we must not forget, that there is a North American 
Unionid-shell (Lastena lata), which also has a foot like this. In the muscle-sears, 
the ligamental sinus, and the beak-sculpture Solenaia undoubtedly differs from 
the South American Mycetopoda, which according to the anatomy is a Muteline- 
shell. 

The species (subsinuata) of which I have studied the anatomy, has another 
character, the partly closed anal-opening, in which it differs from all South American 
Muteline, and resembles the African members of this subfamily. This may be 
another peculiar feature of the genus, but it is desirable that other species should 
be examined as to this. 


66. Mycrropopa sILiquosa (Sprx) (1827). 
Mycetopoda siliquosa Von InerRInG, 1910, p. 120; Stmpson, 1914, p. 1458. 
Mycetopoda bahia Von Inertna, 1910, p. 122, Pl. 12, fig. 3; Supson, 1914, p. 1463. 

According to Simpson, M. legumen (Von Martens) and M. clessini Von Ihering 
belong here. 

Type-locality.—Rio Paraguasst,, Bahia, Brazil. 

Other Localities.—Rio Piracicaba, Piracicaba, Sao Paulo, Brazil (Ven Ihering, 
1893); Rio Sao Francisco, Villa Nova, Sergipe (not Bahia), Brazil (Von Ihering, 
M. bahia). 

New Locality—Lagoa Salgado, Bahia, Brazil (upper Rio Salitré, tributary to 
Sao Francisco) (J. D. Haseman coll., November 10, 1907). Two specimens. Two 


634 MEMOIRS OF THE CARNEGIE MUSEUM. 


other specimens are in the Carnegie Museum, without exact localities, from the 
Holland and Juny collection respectively. 

Distribution.— Restricted to eastern Brazil, to the drainages of the Rio Parana 
in Sao Paulo, and of the Rio Paraguassti and Rio Sao Francisco in Bahia and 
Sergipe. Possibly more widely distributed in the Sao Francisco system. 

Haas (1916, p. 37, 58) gives this species also from Rio Unuyacu (tributary 
to Rio Napo) in Ecuador; however, he conceived it in Simpson’s sense, and we 
cannot be sure that it is M. siliquosa as defined by Von Ihering. 

My specimens fully agree with the account given by Von Ihering, and their 
measurements come very close to those given by him. 


MEASUREMENTS. 


Locatity Length Height Diameter. | Beaks. 


Lagoa Salgado | 72 mm. 26 mm. =36 pr. ct. of L. | 13.5 mm. =17 pr. ct. of L. at 19 mm. =26 pr. et. of L. 
Bolland (colle eter ena |PS0n oe) | 29o) ee 37, 155 oe — 19 £ |} 20 “ =25 ss 
Juny coll... ... Sao Gh, Oa) Pine He Sere * 15 * =18 “ | ° oy S05 G 
Lagoa Salgado... . Rr) [toh “1 35 “  =39 a 20 = - Be 27 “ =30 si 
Spix’ type -. hele : 80 Ge Wen! “ =39 Fa 22 “. =28 x 


The figures for Spix’ type are taken from Von Ihering (1890). Von Ihering 
(1910, in the key) gives the location of the beaks as ranging from 18 to 29 pr. et. 
and the height as ranging from 35 to 37 pr. et. of the length. 

Remarks.—In all of my specimens, the posterior adductor sear is presinual. 
M. bahia is founded upon a single specimen, which has the measurements: L. 78, 
H. 27 = 35 pr. ct., D..15.5 = 20 pr. ct., beaks at 23 = 30 pr. ci. “These figures 
fall within the range of variation of MM. siliquosa. In Von IThering’s key there is 
here a weak point, since the forms are distinguished chiefly by the location of the 
beaks, with the figures partly overlapping. I cannot find any difference in bahia 
from siliquosa, except that the lower margin in the former ascends slightly behind, 
and that the posterior adductor scar is said to be “‘subsinual, in part even a little 
presinual.”’ The first character very well may be individual; the second, dis- 
regarding the fact that it is hard to understand, does not at all differ from siliquosa, 
where this scar is simply presinual. Indeed, my young specimen from Lagoa 
Salgado has the adductor-sear less in advance of the ligamental sinus than the 
larger. Altogether, this young specimen is extremely close to bahia, only the 
posterior lower margin is not curved up, and the beaks are more anterior. It is 
also remarkable for the great thinness and transparency of the shell. Therefore 
I think that M. bahia is only a young individual of M. siliquosa. 


— ee 


i~_ 


ORTMANN: SOUTH AMERICAN NAIADES. 635 


67. Mycrropropa STAUDINGERI (VON InpRING) (1890). 
Mycetopus staudingeri Von IneRING, 1890, p. 130, figs. A, B. 
Mycetopoda staudingeri Simpson, 1900, p. 934; Von Thering, 1910, p. 121. 
Mycetopoda siliquosa staudingeri Simpson, 1914, p. 1460. 

Type-locality.—Rio Huayabamba, Peru (tributary to Rio Huallaga). 

Additional Locality.—Rio Huallaga, Peru (Von Ihering). 

Locality Represented in Carnegie Museum.—Maranon, Upper Amazon (Hart- 
man collection). One specimen. 

Distribution. Headwaters of the Amazon in Peru; a variety (equatorialis 
Von Ihering) in Ecuador. 

Our specimen agrees very well with Von Ihering’s description and figures, 
chiefly with fig. A (which is supposed to be a male) but it to a certain degree stands 
between figs. A and B (See measurements of height). The postsinual position 
of the posterior adductor-sear is evident and remarkable, and it seems, indeed, 
that this is an important taxonomic character. The posterior end of the upper 
margin (behind the ligamental sinus) is in my specimen not so greatly elevated 
as in Von Thering’s figures. 


MEASUREMENTS. 
eee eee ee 
My-specimen'. ...2-..<...+ | 94mm. | 38 mm. =40 pr. ct. of L. 19 mm. =20 pr. ct. of L. ‘at 24 mm. =25 pr. ct. of L. 
Von Ihering, A........... 93 ‘ | 35 “ =38 
Do. PD eleas noe ilaR ye A 43 “ =42 7 Za 20, 


In 1910, Von Ihering gives for the height 35 to 37 pr. et. of the length, which 
does not exactly agree with his original figures. The location of the beaks is ac- 
cording to him is 27 to 28 pr. ct. of the length. 


68. MycrToPODA SUBSINUATA (SOWERBY) (1868). 

Mycetopus subsinuatus SowERBY, XVI, 1868, Pl. 4, fig. 10; Von Marrens, 1900, 

p. 540, Pl. 41, fig. 5. 
Mycetopoda subsinuata Stupson, 1900, p. 934; Von InerinG, 1910, p. 120; Stupson, 

1914, p. 1461. 

Type-locality.— Bogota, Colombia. 

Other Localities —Ecuador (Von Ihering); Paso Antonio, West Guatemala 
(Pacific slope) (Von Martens). 

New Localities—Maranon,. Upper Amazon (Peru) (Hartman coll.). Three 
complete specimens, four left valves. Rio Conchins, Maya Farm, Quirigua, 
Guatemala (Atlantic slope, to Rio Montagua) (A. A. Hinkley coll., February 6, 


636 MEMOIRS OF THE CARNEGIE MUSEUM. 


1913). One shell, female, with soft parts, and soft parts of a male and female with- 
out shells. 

Distribution.—From the upper Amazon drainage in Peru and Ecuador through 
Colombia into Central America, northward to Guatemala, where it is found both 
on the Atlantic and Pacific slopes. 

Von Ihering’s key has failed me in the identification of this species, since he 
uses size as a criterion, while my specimens are all rather small. The height, 
also used as a distinctive character, is apparently unreliable, as shown by my 
specimens. Therefore this eroup (hh in the key) needs revision. 

Nevertheless the two largest specimens at hand (one from the upper Amazon, 
the other from Guatemala) agree fairly well with Von Ihering’s account and 
measurements, and also with those of Von Martens. There is no question about 
the identity of the Central American specimens with the form from northern South 
America. The posterior adductor-sear is said to be subsinual (Von Ihering p. 118). 
This fits my smaller specimens from the upper Amazon, while the larger one is 
peculiar.. It appears as if there were in each valve two superimposed sears, the 
one more anterior, the other a little farther back. The latter is superficial, but ap- 
parently corresponds to the latest growth-addition to the shell. Its anterior end 
is slightly in advance of the ligamental sinus (presinual). In this specimen, how- 
ever, there is a disturbance of the regular growth, as indicated by a strong growth- 
rest on the outside of the shell, and the shell looks as if stunted behind. This 
individual is therefore not normal. In the large specimen from Guatemala, the 
sear is also slightly presinual (about one-third of the retractor-process projecting 
in front of the sinus), and in Von Martens’ figure (representing a very large speci- 
men) this sear is still more presinual. 

The sinuosity of the lower margin is seen in my two larger specimens, but is 
not so strong as in Sowerby’s and Von Martens’ figures. The young specimens, 
which undoubtedly belong with the larger one, show hardly a trace of this sinuosity. 


MEASUREMENTS. 
Locality. No. | Sex. | Length. | Height. Diameter. Beaks. 

= } | | 
Maranon 1 2 58 mm. 17 mm. =29 pr. ct. of L. 10 mm.=17 pr. ct. of Lat 15 mm. =26 pr. et. of L. 

Do. 2 ? 65 oe LO ee — 30 = 10 “ =16 = 17 ii s 

Do. Bo? roe alee 31 fs 12 “ =16 tf 2027 Gb: 

Do. <s 4 ? Chine 23 “ =31 12 =16 3 | 20 co =27 ‘a 
Guatemala. : | 9 86> (28 4 88 - ibGay 22 = e10) “ Zh ea se 
Miararion!. .. fees. 5 | 2 (88) 5 Lee “g ) 20 “ =(23 “ ) 26 “ =(30 ie ) 
Sowerby....... 1 | 41 =35 2 - 

Von Martens: | 125 “ | 43 =34 ue WO Sis : 
Do. , : | 132 45 =34 23 : 17 29 or = 


ORTMANN: SOUTH AMERICAN NAIADES. 637 


My specimen, No. 5, from the Marajon is the one, which probably is injured, and 
the length probably would be greater, when normal; this, of course, has influence on 
the other indices, which are all somewhat too high. The figures taken from Sowerby 
and Von Martens are close to mine. The greater height undoubtedly is due to 
the larger size of the specimens, and probably also to the more anterior location of 
the beaks. 

Anatomy.—Soft parts of one male and two females at hand, one of the latter 
is gravid (collected February 6). 

The anatomy is that of the South American Mutelinw, but it resembles that 
of the African Muteline, in having the anal opening closed above for about half 
of its length. The opening is therefore comparatively short, being only a little 
longer than the branchial opening, and reaching upward only to about the middle 
of the adductor muscles. In other South American Muteline it reaches upward 
beyond the posterior retractor-muscles. The anal is separated from the branchial 
opening by a connection of the mantle; its inner edge is smooth. Branchial opening 
with fine papillee on the inner edge. Although Simpson says that the branchial 
opening is closed below, I cannot find any trace of a mantle-connection at the lower 
(anterior) end. There is also no indication that such a connection has been torn 
during life, or in preservation. Palpi long and low, their lower margins curved, 
not drawn out into a posterior point, posteriorly with a short truncation, forming 
the posterior margins, which are not connected. 

Foot very large, subcylindrical and subcompressed, at the distal end swollen 
into a button-like knob. This structure is likewise not seen in other Muteline 
shells. 

Gills long and narrow, the inner the wider, the anterior ends as usual. Inner 
lamina of inner gill entirely connected with abdominal sac. Distinct, continuous 
septa of the Muteline type are present. The inner gill of the female is marsupial, 
with thicker, but not more crowded, septa; the water-tubes are again divided by 
vertical ridges into an inner and outer compartment, the inner of which serves as 
ovisac, the outer as secondary water-canal. Eggs small, loosely hanging together. 
I have not been able to find mature larve in my gravid female. 


Genus Lemna Gray (1840). 
Simpson, 1914, p. 1399. 


The chief character of this genus is the sinus of the pallial line below the pos- 
terior adductor-sear, which is said to be connected with the closing of the branchial 
opening at its lower (anterior) end, but particulars about this are not known. 

In other respects the shell of this genus is very similar to that of the species 


638 MEMOIRS OF THE CARNEGIE MUSEUM. 


of the trapesialis-group of Anodontites, with which it also has in common the gaping 
margins. A peculiar character, generally missing in South American Muteline, 
is the presence of an oblique row of dorsal muscle-sears in the beak-cavity. 

There can be hardly any question that this genus represents a more highly 
specialized type of the genus Anodontites, and that its root is in the trapesialis- 
group. Its distribution extends over South America, east of the Andes, and from 
the basin of the Amazon southward to northern Argentina. 

The genus Leila is in great confusion, although there seem to exist only a 
few species. Its revision has been attempted by Von Ihering (1890, p. 39) and 
by Simpson, (1900, p. 914), but these two authors have arrived at very different 
conclusions. Both agree in recognizing two groups: the one containing species 
with a practically straight hinge-line (L. blainvilleana and L. spixi), the other 
species with a curved or sinuate hinge-line. While Simpson unites all of the forms 
belonging to the latter group, into one species (L. esula), Von Thering distinguishes 
three as valid. 

My material is entirely insufficient to permit me to decide this point. The 
specimens before me unquestionaly come under L. castelnaudi Hupé, and so I shall 
record them under this name, without attempting to pass upon the question 
whether then are different from esula D’Orbigny and from pulvinata Hupé. They 
also agree fairly well with Von Ihering’s description of castelnaudi. 


69. LEILA CASTELNAUDI Hup& (1857). 

Leila castelnaudi Hurt, 1857, p. 91, Pl. 19, fig. 1. 
Anodon castelnaudi SowERBY, XVII, 1868, Pl. 20, fig. 79. 
Columba castelnaudi Von InErina, 1890, pp. 139, 142. 

According to Simpson (1914, p. 1401) this is identieal with L. esula (D’Orbigny). 

Type-locality.—‘‘ Bourbon ou Olympo, Paraguay.” This probably is Fuerte 
Olympo, on Rio Paraguay, northern Paraguay. 

New Localities—Rio Paraguay, Corumbé, Matto Grosso, Brazil (H. H. 
Smith coll.). One left valve. Swamp of Lambaré, Asuncién, Paraguay (J. D. 
Haseman coll., March 31, 1909). One left valve. . 


M8rASUREMENTS. 


Locality. Length. | Height. | Diameter. | Beaks. | Hinge-line. 
V. Ihering 138 mm. | 96 mm. =70 pr.ct. of L. 105 mm. =76 pr.et. of L. 
Asuncion .| 158 “ |112 “ =71 2 88 mm. =43 pr. et. of L. at 48 mm. =30 pr. ct. of L101 ‘* =64 
Corumbé. 166 “ |116 =70 fs 20'. (t= 42 i 52 “ =31 A 114 “ =69 a 


Von Ihering has measured according to a peculiar method, but I see no par- 


ORTMANN: SOUTH AMERICAN NAIADES. 639 


ticular advantage in this. Yet the length of the hinge-line from its anterior end 
to the anterior end of the ligamental sinus, and its proportion to the length of the 
shell, should be noted, because there are slight differences in our specimens in this 
respect. 

According to Hupé’s figure, the beaks are located at 44 mm. = 32 pr. ct. of 
length. This and the height given by Von Ihering agree very well with my speci- 
mens, but the proportion of the hinge-line to the total length is less in the latter. 
But the figures for my specimens show that that there is variation in this respect. 


BIBLIOGRAPHY. 


1858 Apams, H. & Apams, A. The Genera of Recent Mollusca. Vol. II, London, 
1858. 

1906 Bartscu, P. Descriptions of Two New Naiades (Proc. U. 8S. Nat. Mus., XXX, 
1906, pp. 393-395). 

1900-1901 Corst, A. F. Moluscos de la Reptiblica Oriental del Uruguay (Anal. Mus. 
Nac. Montevideo, II, 1900, pp. 445-448; 1901, pp. 449-481). 

1911 Eraenmann, C. H. The Localities at which Mr. John D. Haseman Made Col- 
lections (Ann. Carnegie Mus. VII, 1911, pp. 299-314). 

1915 Frierson, L. 8. A New Pearly Freshwater Mussel of the Genus Hyria from 
Brazil (Proc. U. 8. Nat. Mus., XLVII, 1915, p. 363). 

1910 Gerrmatn, L. Mission du Service géographique de l’Armée pour la Mesure d’un 
Are de Meridien Equatorial en Amérique du Sud. IX, Zodl., Fase. 3, Etude 
sur les Mollusques Terrestres et Fluviatiles. 1910, pp. C. 63-C. 68. 

1834 GrirrirH, E. The Animal Kingdom by the Baron Cuvier. XII, 1834. 

1916 Haas, F. Nayades del Viaje al Pacifico (Trab. Mus. Ciene. Nat. Madrid., 
Zool., No. 25, 1916, pp. 1-63). 

1911 Haseman, J. D. A brief Report upon the Expedition of the Carnegie Museum 
to Central South America (Ann. Carnegie Mus., VII, 1911, pp. 287-299). 

1857 Hurt, H. Mollusques, in Casretnau, F. Dr, Animaux nouveaux ou rares 
recueillis pendant l’Expédition dans les parties centrales de |’Amérique du 
Sud. 1857, pp. 1-103. 

1890 Inertnc, H. Von, Revision der von Spix in Brasilien gesammelten Najaden 
(Arch. f. Naturgesch., 1890, I, pp. 117-170). 

1891-1892 THERING, H. Von, Anodonta und Glabaris (Zoolog. Anzeig., XIV, 1891, 
pp. 474-484; Ibid., XV, 1892, pp. 1-5). 

1893 Inertne, H. Von, Najaden von 8. Paulo und die geographische Verbreitung der 
Suesswasserfauna von Siidamerika (Arch. f. Naturgesch., 1893, I, pp. 45- 
140). 

1910 Inertnc, H. Von. Ueber Brasilianiseche Najaden (Abh. Senckenberg. Naturf. 
Ges., XXXII, 1910, pp. 113-140). 


640 


1915 


1819 


MEMOIRS OF THE CARNEGIE MUSEUM. 


TnertmNG, H. Von. Molluscos, in Commissao de Linhas Telegraphicas Estra- 
tegicos de Matto Grosso ao Amazonas. Ann. V, 1915, pp. 1-14. 
Lamarck, J. B. pr. Histoire Naturelle des Animaux sans Vertébres, VI, 1819. 


1832-1874 Lra,I. Observations on the Genus Unio. Vols. I-XIII, 1832-1874. 


1870 


1917 


1885 


1894 


1895 


1900 


1893 


1918 


1835 


19116 


191 le 


1912 


1918 


1893 


Lea, I. Synopsis of the Family Unionide. Fourth edition, 1870. 

MarsHauit, W. B. New and Little-known Species of South American Fresh- 
water Mussels of the Genus Diplodon (Proce. U.S. Nat. Mus. LITT, 1917, pp. 
381-388). 

Martens, E. Von. Ueber brasilische Land- und Suesswasser-Mollusken. (Sitz. 
Ber. Gesellsch. naturf. Fr. Berlin, 1885, pp. 147-149). ; 
Martens, E. Von. Die von Dr. Bohls in Paraguay gesammelten Mollusken 

(Sitz. Ber. Gesellsch. naturf. Fr. Berlin, 1894, pp. 163-170). 

Martens, E. Von. Mollusken von Paraguay (Sitz. Ber. Gesellsch. naturf. 
Fr. Berlin, 1895, pp. 33-35). 

Martens, E. Von. Biologia Centrali-Americana. Land and Freshwater Mol- 
lusea. 1900-1901. (Unionide, pp. 478-540, 1900). 

Neurine, A. Ueber Najaden von Piracicaba in Brasilien (Sitz. Ber. Gesellsch. 
naturf. Fr. Berlin, 1893, pp. 159-167). 

OpunerR, N. H. Zur Kenntnis der Homologien des Bivalvenschlosses (Geolog. 
Foren. Stockholm Férhandl., 1918, pp. 562-590). 

Orpicny, A. D’. Synopsis terrestrium et fluviatilium Molluscorum in suo per 
Americam Meridionalem Itinere (Magas. de Zoolog., 1835). 

Orpiany, A. D’. Voyage dans l’Amérique Méridionale, V, part 3, Mollusques. 
1835-1848. 

Or?TMANN, A. E. The Soft Parts of Spatha kamerunensis. Walker (Nautilus, 
XXIV, 1910, pp. 39-42). 

OrtTMANN, A. KE. The Anatomical Structure of Certain Exotie Naiades compared 
with that of the North American Forms (Nautilus, XXIV, 1911, pp. 103-108; 
114-120; 127-131). 

OrtTMANN, A. E. A Monograph of the Naiades of Pennsylvania (Mem. Car- 
negie Mus., IV, 1911, pp. 279-347). 

OrTMANN, A. E. The use of the Generic Names Unio, Margaritana, Lymnium, 
and Elliptio, and of Anodonta and Anodontites (Nautilus, XXV, 1911, pp. 
88-191). 

Orrmann, A. E. The Anatomy of the Naiad Hyridella australis (Lamarck) 
(Nautilus, XXV, 1912, pp. 100-103). 

OrtMANN, A. E. The Anatomy of two African Naiades, Unio caffer and Spatha 
wahlbergi (Nautilus, XX XI, 1918, pp. 75-78). 

Piuspry, H. A. Notes on the Genera of Unionide and Mutelide (Nautilus, 
VII, 1893, p. 30). 


1896 


1911 


1896 


ORTMANN: SOUTH AMERICAN NAIADES. 641 


Pruspry, H. A. New Species of Freshwater Mollusks from South America (Proc. 
Acad. Nat. Sci. Philadelphia, XLVIII, 1896, pp. 561-565). 

Pruspry, H. A. Non-marine Mollusca of Patagonia, in Rep. Princeton Univ. 
Exped. to Patagonia, IIT, part 5, 1911, pp. 609-610. 

Piussry, H. A. & Rusw, W. H. List, with Notes, of Land and Freshwater Shells 
Collected by Dr. Wm. H. Rush in Uruguay and Argentina (Nautilus X 
1896, pp. 76-79). 


, 


1864-1870 Rerve, L. A. & Sowersy, G. B. Conchologia Iconica. Vols. XVI-XVII, 


1900 


1914 


1827 


1840 


(genera Unio, Mycetopus, A nodon, Hyria, Castalia) 1864-1870. 

Rusu, W. H., see: Pinssry & Rusu. 

Srupson, C. T. Synopsis of the Naiades or Pearly Freshwater Mussels (Proc. 
U.S. Nat. Mus., XXII, 1900, pp. 501-1044). 

Smpson, C. T. A Descriptive Catalogue of the Naiades or Pearly Freshwater 
Mussels. Detroit, 1914. 

SowWERBY, G.S., see REEVE & SowERBy. 

Sprx, J. B. pe & Wacner, J. A. Testacea fluviatilia que in itinere per Brasiliam 
collegit. 1827. 

Swainson, W. A Treatise on Malacology. London., 1840. 

Waaner, J. A., see Sprx & WAGNER. 


(Note: As to the authorship of the species described by Spix and Wagner, Cf. Von 


Thering, 1890, pp. 118-119, footnote). 


642 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XXXIV. 
SHELLS OF DIPLODON HASEMANI ORTMANN AND DIPLODON IMITATOR ORTMANN. 
All figures natural size. 


Fies. 1-4. Diplodon hasemani Ortmann, from Rio Guaporé, near Rio Sao Simao, 
Matto Grosso, Brazil. Carn. Mus. Cat. No. 61.5857. 

Fia. la. Adult male (No. 10), lateral view. 

Fie. 1b. Adult male (No. 10), dorsal view. 

Fie. 2a. Adult, gravid female (No. 9), lateral view. 

Fig. 2b. Adult, gravid female (No. 9), inner view of left valve. 

Fig. 2c. Adult, gravid female (No. 9), inner view of right valve. 

Fie, 3. Half-grown, gravid female (No. 4), lateral view. 

Fia 4. Young, gravid female (No. x), lateral view. 

Fies. 5-7. Diplodon imitator Ortmann, from Rio Vaccahy-mirim, Santa Maria, 
Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.9248. (See also Pl. XXXYV, figs. 1 
and 2). 

Fig. 5a. Half-grown male (No. 29), lateral view. 

Fie. 5b. Half-grown male (No. 29), inner view of left valve. 

Fia. 5c. Half-grown male (No. 29), inner view of right valve. 

Fia. 5d. Half-grown male (No. 29), dorsal view. 

Fic. 6a. Young male (No. 14), lateral view. 

Fia. 6b. Young male (No. 14), dorsal view. 

Fia. 7a. Adult female (No. 33), inner view of left valve (see also Pl. XX XV, fig. 1). 

Fie. 7b. Adult female (No. 33), inner view of right valve. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XXXIV. 


ێ 3 


4 


DIpPLopon. 


644. MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XXXV. 


SHELLS OF DIPLODON IMITATOR ORTMANN, DIPLODON SIMILLIMUS ORTMANN, AND 
DiIPLODON VICARIUS ORTMANN. 


All figures natural size. 


Fias. 1 AND 2. Diplodon imitator Ortmann, from Rio Vaceahy-mirim, Santa Maria, 
Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.9248 (See also Pl. XX XIV, figs. 5-7). 

Fia. 1. Adult female (No. 33), lateral view (same specimen as that figured on 

Pl. XXXIV, fig. 7). 

Fia. 2. Young, gravid female (No. 21), lateral view. 

Fias. 3-6. Diplodon simillimus Ortmann, from Rio Nhundiaquara, Morretes, 
Paranda, Brazil. Carn. Mus. Cat. No. 61.9250. 

Fie. 8. Half-grown male (No. 11), lateral view. 

Fie. 4. Half-grown male (No. 16), lateral view. 

Fia. 5a. Adult, gravid female (No. 22), lateral view. 

Fie. 5b. Adult, gravid female (No. 22), dorsal view. 

Fie. 5c. Adult, gravid female (No. 22), inner view of left valve. 

Fia. 5d. Adult, gravid female (No. 22), inner view of right valve. 

Fic. 6a. Young, gravid female (No. 24), lateral view. 

Fic. 6b. Young, gravid female (No. 24), dorsal view. 

Fies. 7 AND 8. Diplodon vicarius Ortmann, from creek (Rio Ribeira drainage), 
Aqua Quente, near Iporanga, Sao Paulo, Brazil. Carn. Mus. Cat. No. 61.9251 (See also 
Pl. XXXVI, figs. 1 and 2). 

Fia. 7. Half-grown male (No. 13), lateral view. 

Fie. 8. Adult female (No. 15), lateral view (See also Pl. XXXVI, fig. 1). 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. 


PLATE XXXV. 


DIPLopon. 


we 


646 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XXXVI. 


SHELLS OF DIPLODON VICARIUS ORTMANN, DIPLODON DECIPIENS ORTMANN, AND 
DIPLODON HILD# ORTMANN. 


All figures natural size. 


Fies. 1 anp 2. Diplodon vicarius Ortmann, from creek (Rio Ribeira drainage), 
Aqua Quente, near Iporanga, Sao Paulo, Brazil. Carn. Mus. Cat. No. 61.9251 (See 
also Pl. XX XV, figs. 7 and 8). 

Fic. la. Adult female (No. 15), dorsal view (same specimen as that figured on 

Pl. XXXV, fig. 8). 

Fia. 1b. Adult female (No. 15), inner view of left valve. 

Fie. le. Adult female (No. 15), inner view of right valve. 

Fie: 2: Half-grown, gravid female (No. 9), lateral view. 

Fras. 3-6. Diplodon decipiens Ortmann, from creek (tributary to Rio Iguassu), 
Serrinha, Parana, Brazil. Carn. Mus. Cat. No. 61.9253. 

Fie. 3a. Adult male (No. 4), lateral view. 

Fig. 3b. Adult male (No. 4), inner view of left valve. 

Fie. 3c. Adult male ( 

Fic. 3d. Adult male (No. 4), dorsal view. 

Fia. 4. Adult female (No. 6), lateral view. 
Fig. 5. Half-grown, gravid female (No. 3), lateral view. 
Fic. 6a. Young female (No. c), lateral view. 


No. 4), inner view of right valve. 


Fic. 6b. Young female (No. ¢), dorsal view. - 

Fie. 7. Diplodon hilde Ortmann, from Rio Jacuhy, Cachoeira, Rio Grande do 
Sul, Brazil. Carn, Mus. Cat. No. 61.5864 (See also Pl. XX XVII, figs. 1-3). 

Fic. 7a. Nearly full grown male (No. q), lateral view. 

Via. 7b. Nearly full grown male (No. q), dorsal view. 


DIPLODON. 


w a ~ 
tesa i ir a at ree 


Ss 


Se eee 


Oa eee ies, = 
ce et ig: aiden, 


648 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XXXVII. 
SHELLS OF DIPLODON HILDA) ORTMANN AND DIPLODON MOGYMIRIM ORTMANN. 
All figures natural size. 


Frias. 1-8. Diplodon hilde Ortmann, from Rio Jacuhy, Cachoeira, Rio Grande do 
Sul, Brazil. Carn. Mus. Cat. No. 61.5864 (See also Pl. XXXVI, fig. 7). 

Fie. la. Young male (No. d), lateral view. 

Fie. 1b. Young male (No. d), dorsal view. 

Fia. 2a. Adult female (No. 15), lateral view. 

Fie. 2b. Adult female (No. 15), dorsal view. 

Fia. 2c. Adult female (No. 15), inner view of left valve. 

Fie. 2d. Adu't female (No. 15), inner view of right valve. 

Fig. 38. Half-grown female (No. h), lateral view. 

Fras. 4-7. Diplodon mogymirim Ortmann, from creek (tributary to Rio Mogy 
Guassti), Mogy Mirim, Sao Paulo, Brazil. Carn. Mus. Cat. No. 61.9260. 

Fie. 4a. Adult male (No. 22), lateral view. 

Fia. 4b. Adult male (No. 22), inner view of left valve. 

Fic. 4c. Adult male (No. 22), inner view of right valve. 

Fia. 5a. Half-grown male (No. 9), lateral view. 

Fie. 5b. Half-grown male (No. 9), dorsal view. 

Fic. 6a. Young male (No. 12), lateral view. 

Kia. 6b. Young male (No. 12), dorsal view. 

Fig. 7a. Adult female (No. 38), lateral view. 

Fic. 7b. Adult female (No. 38), dorsal view. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XXXVII. 


DIPLODON. 


650 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XXXVIIFE. 
SHELLS OF DIPLODON BERTHA ORTMANN AND DIPLODON ENNO ORTMANN. 
All figures natura! size. 


Fras. 1-4. Diplodon berthe Ortmann, from Rio Jacuhy, Cachoeira, Rio Grande 
do Sul, Brazil. Carn. Mus. Cat. No. 61.5865. 

Fig. la. Adult male (No. 24), lateral view. 

Fia. 1b. Adult male (No. 24), dorsal view. 

Fia. le. Adult male (No. 24), inner view of left valve. 

Fig. ld. Adult male (No. 24), inner view of right valve. 

Fia. 2a. Young male (No. 3), lateral view. 


Fia. 2b. Young male (No. 3), dorsal view. 

Fig. 3a. Gravid female (No. 10), lateral view. 

Fia. 3b. Gravid female (No. 10), dorsal view. 

Fia. 4. Gravid female (No. 16), lateral view. 

Frias. 5-8. Diplodon enno Ortmann, from Rio Grande (Sao Francisco drainage), 
Boqueirao, Bahia, Brazil. Carn. Mus. Cat. No. 61.9264. 

Fie. 5. Half-grown male (No. 4), lateral view. 

Fia. 6a. Young male (No. 12), lateral view. 

Fic. 6b. Young male (No. 12), dorsal view. 

Fra. 7. Adult female (No. 1), lateral view. 

Fia. 8a. Nearly adult female (No. 2), lateral view. 

Fia. 8b. Nearly adult female (No. 2), dorsal view. 

Fia. 8c. Nearly adult female (No. 2), inner view of left valve. 

Fia. 8d. Nearly adult female (No. 2), inner view of right valve. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XXXVIIL. 


DIPLopDON. 


MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XXXIX. 


SHELLS OF DrPLODON DECEPTUS (Srmpson), DrpLopoNn (CycLOMYA) PARANENSIS (LEA), 


AND CASTALIA UNDOSA VON MARTENS. 


All figures natural size. 


Fias. 1-5. Diplodon deceptus (Simpson), from Rio Jacuhy, Cachoeira, Rio Grande 
do Sul, Brazil. Carn. Mus. Cat. No. 61.5868. 


Fia. 
Fie. 
Binge 
Fie. 
Fig. 
Fia. 


la. 
1b. 
le. 


Kia. 4 


Fic. 
Fia. 


5a. 


5b. 


Adult male (No. 10), lateral view. 
Adult male (No. 10), dorsal view. . 
Adult male (No. 10), inner view of left valve. 
Adult male (No. 10), inner view of right valve. 
Adult male (No. 11), lateral view. 
Half-grown male (No. 4), lateral view. 
Half-grown female (No. 6), lateral view. 
Young specimen (sex ?) (No. 2), lateral view. 
Young specimen (sex ?) (No. 2), dorsal view. 


Fias. 6 AnD 7. Diplodon (Cyclomya) paranensis (Lea). 


iRnGs 


6. 


Argentina. 


Nearly adult female (No. a), lateral view, from Rio de la Plata, San Isidro, 
Carn. Mus. Cat. No. 61.9265. 


Fie. 7. Young specimen, lateral view, from Rio Paraguay, Corumba, Matto 
Grosso, Brazil. Carn. Mus. Cat. No. 61.2031. 


Fig. 


8. 


Castalia undosa Von Martens, from Rio Tieté, Itapura, Sao Paulo, Brazil. 


Carn. Mus. Cat. No. 61.5116. 


Fie. 
Fia. 
Fia. 
Fie. 


Sa. 
Sb. 
Sc. 
Sd. 


Half-grown specimen, lateral view. 

Half-grown specimen, dorsal view. 

Half-grown specimen, inner view of left valve. 
Half-grown specimen, inner view of right valve. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XXXIX 


DIPLODON and CASTALIA. 


654 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XL. 


SHELLS OF PRISODON ALATUS (SOWERBY), MONOCONDYL#A OBESA ORTMANN, AND 
ANODONTITES CRISPATA BRUGUIDRE. 


All figures natural size. 


Fias. 1-8. Prisodon alatus (Sowerby), from Rio Tapajos, Santarem, Para, Brazil. 
Carn. Mus. Cat. No. 61.5109. 

Fig. 1. Adult specimen, lateral view. 

Fie. 2a. Half-grown specimen, lateral view. 

Fie. 2b. Half-grown specimen, dorsal view. 

Fie. 2c. Half-grown specimen, inner view of left valve. 

Fig. 2d. Half-grown specimen, inner view of right valve. 

Fic. 3. Young specimen, lateral view. 

Fias. 4-6. Monocondylea obesa Ortmann, from Rio Tapajos, Santarem, Para, 
Brazil. Carn. Mus. Cat. No. 61.5850. 

Fic. 4a. Half-grown specimen (No. 10), lateral view. 

Fic. 4b. Half-grown specimen (No. 10), inner view of left valve. 

Fic. 4c. Half-grown specimen (No. 10), inner view of right valve. 

Fie. 5a. Young specimen (No. 5), lateral view. 

Fie. 5b. Young specimen (No. 5), dorsal view. 

Fic. 6. Young specimen (No. 1), lateral view. 
Fias. 7 AND 8. Anodontites crispata Bruguiére, from Rio de la Paila, Paila, U. S. 

[of Colombia. Carn. Mus. Cat. No. 61.9274 (See also Plate XLI, figs. 2 and 3). 
\ Fig. 7a. Half-grown male (No. 8), lateral view. 
Fie. 7b. Half-grown male (No. 8), dorsal view. 
Fic. 8. Nearly adult female (No. 10), lateral view. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XL 


Prisopon, MonocoNDYL®A, ANODONTITES. 


656 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XLI. 


SHELLS OF MONOCONDYLAEA HOLLANDI ORTMANN, ANODONTITES CRISPATA BRUGIERE, 
AND ANODONTITES CLESSINI (FISCHER). 


All figures natural size. 


Fic. 1. Monocondylea hollandi Ortmann, from Rio Guaporé, near Rio Sao SimAo, 
Matto Grosso, Brazil. Carn. Mus. Cat. No. 61.5846. 

Fia. la. Holotype, male, lateral view. 

Fic. 1b. Holotype, male, dorsal view. 

Fic. le. Holotype, male, inner view of right valve. 

Fics. 2 anp 3. Anodontites crispata Bruguiére, from Rio de la Paila, Paila, U. S. 
of Colombia. Carn. Mus. Cat. No. 61.9274 (See also Plate XL, figs. 7 and 8). 

Fie. 2a. Nearly adult specimen (sex ?), lateral view. 

Fic. 2b. Nearly adult specimen (sex ?), inner view of right valve. 

Fig. 38. Young specimen (sex ?), lateral view. 

Fie. 4. Anodontites clessini (Fischer), from Rio Vaceahy-mirim, Santa Maria, 
Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5820 (See also Plate XLII, figs. 1 
and 2). Male (No. 12), lateral view (See also Plate XLII, fig. 1). 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XLI 


MonoconDyL@®A, ANODONTITES. 


i 


aD) 
257 
as 


M. — 


fy ke 
Peer 


658 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XLII. 


SHELLS OF ANODONTITES CLESSINI (FISCHER), ANODONTITES HYRIOIDES ORTMANN, 
ANODONTITES HASEMANI ORTMANN, AND ANODONTITES IHERINGI (CLESSIN). 


All figures natural size. 


Fies. 1 anp 2. Anodontites clessini (Fischer), from Rio Vaccahy-mirim, Santa 
Maria, Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5820 (See also Plate XLI, 
fig. 4). ‘ 

Fic. 1. Male (No. 12), dorsal view (Same specimen as that figured on Pl. XLI, 
fig. 4). 

Fic. 2a. Female (No. 11), lateral view. 

Fic. 2b. Female (No. 11), inner view of right valve. 

Fras. 8-5. Anodontites hyrioides Ortmann, from Rio Tapajos, Santarem, Para, 
Brazil. Carn. Mus. Cat. No. 61.5829. 

Fic. 3a. Largest specimen (No. 6), lateral view. 

Fic. 3b. Largest specimen (No. 6), inner view of right valve. 

Fra. 4a. Half-grown specimen (No. 4), lateral view. 

Fic. 4b. Half-grown specimen (No. 4), dorsal view. 

Fia. 5. Young specimen (No. 1), lateral view. 

Fies. 6 AND 7. Anodontites hasemani Ortmann, from Rio Paraguay, Santa Rita, 
Matto Grosso, Brazil. Carn. Mus. Cat. No. 61.5832. 

Fic. 6a. Half-grown male (No. 1), lateral view. 

Fic. 6b. Half-grown male (No. 1), inner view of left valve. 

Fia. 7a. Gravid female (No. 3), lateral view. 

Fic. 7b. Gravid female (No. 3), dorsal view. 

Fig. 8. Anodontites theringi (Clessin), from Rio Vaccahy-mirim, Santa Maria, 
Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5815 (See also Plate XLII, fig. 1, 
and Plate X LIV, fig. 1). 

Fic. 8a. Half-grown male (No. 1), lateral view. 

Fic. 8b. Half-grown male (No. 1), dorsal view, 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XLII. 


ANODONTITES. 


660 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XLIII. 


SHELLS OF ANODONTITES IHERINGI (CLESSIN), ANODONTITES RIOGRANDENSIS (VON 
IHERING), AND ANODONTITES FORBESIANA (LBA). 


All figures natural size. 


Fic. 1. Anodontites theringi (Clessin), from Vaccahy-mirim, Santa Maria, Rio 
Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5815 (See also Plate XLII, fig. 8, and 
Plate XLIV, fig. 1). 

Adult female (No. 3), lateral view (See also Plate XLIV, fig. 1). 

Fias. 2 AND 8. Anodontiles riograndensis (Von Ihering), from Rio de la Plata, 
San Isidro, Argentina. Carn. Mus. Cat. No. 61.9279 (See also Plate XLIV, fig. 2). 

Fig. 2a. Adult male (No. x), lateral view. 

Fia. 2b. Adult male (No. x), dorsal view. 

Fic. 3. Adult, gravid female (No. z), lateral view (See also Plate XLIV, fig. 2). 

Fia. 4. Anodontites forbesiana (Lea), from Rio Uruguay, Uruguayana, Rio Grande 
do Sul, Brazil. Carn. Mus. Cat. No. 61.9280 (See also Plate XLIV, fig. 3). Half- 
grown male (No. 8), lateral view. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII 


ANODONTITES. 


662 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XLIV. 


SHELLS OF ANODONTITES IHERINGI (CLESSIN), ANODONTITES RIOGRANDENSIS (VON 
IHERING), AND ANODONTITES FORBESIANA (LEA). 


All figures natural size. 


Fie. 1. Anodontites theringt (Clessin), from Rio Vaccahy-mirim, Santa Maria, 
Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5815 (See also Plate XLII, fig. 8, 
and Plate XLIII, fig. 1). Adult female (No. 3), inner view of right valve (Same specimen 
as that figured on Plate XLIII, fig. 1). 

Fie. 2. Anodontites riograndensis (Von Ihering), from Rio de la Plata, San Isidro, 
Argentina, Carn. Mus. Cat. No. 61.9279 (See also Plate XLIII, figs. 2 and 3). Adult, 
gravid female (No. z), inner view of right valve (Same specimen as that figured on Plate 
XLII, fig. 3). 

Fie. 3. Anodontites forbesiana (Lea), from Rio Uruguay, Uruguayana, Rio Grande 
do Sul, Brazil. Carn. Mus. Cat. No. 61.9280 (See also plate XLII, fig. 4). 

Fia. 3a. Nearly adult female (No. 11), lateral view. 

Fic. 3b. Nearly adult female (No. 11), dorsal view. 

Fig. 3c. Nearly adult female (No. 11), inner view of right valve. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XLIV. 


ANODONTITES. 


664 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XLV. 


GILLS OF DIPLODON IMITATOR ORTMANN, DIPLODON SIMILLIMUS ORTMANN, DrPLODON 
VICARIUS ORTMANN, AND DIPLODON DECIPIENS ORTMANN. 


All figures represent the left gills magnified to twice natural size, the inner gill to the left, 
the outer gill to the right. 


Fie. 1. Diplodon imitator Ortmann, from Rio Vaccahy-mirim, Santa Maria, Rio 
Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.9248. 

Fic. la. Gills of male (No. 29) (Shell of this specimen figured on Plate XXXIV, 

fig. 5). 

Fig. 1b. Gills of female (No. 32). 

Fie. 2. Diplodon simillimus Ortmann, from Rio Nhundiaquara, Morretes, Parand, 
Brazil. Carn. Mus. Cat. No. 61.9250. 

Fic. 2a. Gills of male (No. 7). 

Fig. 2b. Gills of female (No. 23). 

Fie. 3. Diplodon vicarius Ortmann, from creek (Rio Ribeira drainage), Aqua 
Quente, near Iporanga, Sao Paulo, Brazil. Carn. Mus. Cat. No. 61.9251. Gills of 
female (No. 14). 

Fic. 4. Diplodon decipiens Ortmann, from creek (tributary to Rio Iguassiti), 
Serrinha, Paranda, Brazil. Carn. Mus. Cat. No. 61.9253. 

Fic. 4a. Gills of male (No. 2). 

Fia. 4b. Gills of female (No. 6) (Shell of this specimen figured on Plate XXXVI, 

fig. 4). 


PLATE XLV. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. 


ANATOMY OF DIFLODON. 


666 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XLVI. 


GILLS OF DrpLopON pAuLIsTA (VON IHERING), DipLopon Pickus (LEA), DreLopon 
HILD# ORTMANN, DIPLODON BURROUGHIANUS (LEA), DipLODON MOGYMIRIM 
ORTMANN, DIPLODON BERTHA ORTMANN, AND DrPLODON ENNO ORTMANN. 


All figures represent left gills magnified to twice natural size, the inner gill to the left, 
the outer gill to the right. 


Fig. 1. Diplodon paulista (Von Thering), from Rio Tieté, Mogy das Cruzes, Sao 
Paulo, Brazil. Carn. Mus. Cat. No. 61.9294. Gills of female (No. 4). 

Fie. 2. Diplodon piceus (Lea), from Rio Uruguay, Uruguayana, Rio Grande do 
Sul, Brazil. Carn. Mus. Cat. No. 61.5862. Gills of female (No. 7). 

Fie. 3. Diplodon hilde Ortmann, from Rio Jacuhy, Cachoeira, Rio Grande do 
Sul, Brazil. Carn. Mus. Cat. No. 61.5864. Gills of female (No. 15) (Shell of this 
specimen figured on Plate XX XVII, fig. 2). 

Fie. 4. Diplodon burroughianus (Lea), from pond along Rio Negro, Santa Isabel, 
Uruguay. Carn. Mus. Cat. No. 61.5859. Gills of female (No. x). 

Fie. 5. Diplodon mogymirim Ortmann, from creek (tributary to Rio Mogy Guasst) 
Mogy Mirim, Sao Paulo, Brazil. Carn. Mus. Cat. No. 61.9260. 

Fie. 5a. Gills of male (No. 28). 

Fra. 5b. Gills of young female (No. 18). 

Fia. 5c. Gills of adult female (No. 44). 

Fie. 6. Diplodon berthe Ortmann, from Rio Jacuhy, Cachoeira, Rio Grande do 
Sul, Brazil. Carn. Mus. Cat. No. 61.5865. Gills of female (No. 21). 

Fia. 7. Diplodon enno Ortmann, from Rio Grande (Sao Francisco drainage), 
Boqueirao, Bahia, Brazil. Carn. Mus. Cat. No. 61.9264. 

Fie. 7a. Gills of young female (No. 7). 

Pia. 7b. Gills of nearly adult female (No. 2) (Shell of this specimen figured on 

Plate XX XVIII, fig. 8). 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XLVI. 


ANATOMY OF DIPLODON. 


= 


668 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XLVII. 


LEFT GILLS OF DIPLODON DECEPTUS (SIMPSON), CASTALLA NEHRINGI VON IHERING, 
AND RIGHT GILLS OF MONOCONDYL#A LENTIFORMIS LEA AND ANODONTITES 
CLESSINI (FIscHerR); twice natural size; inner gill to the left, 

outer gill to the right (Figs. 1-4). 


HorIZONTAL SECTIONS OF GILLS OF DIPLODON HASEMANI ORTMANN, DIPLODON IMITATOR | 
ORTMANN, AND DIPLODON DECIPIENS ORTMANN; much enlarged; inner 
gill to the left, outer gill to the right (Figs. 5-7). 


Fic. 1. Diplodon deceptus (Simpson), from Rio Jacuhy, Cachoeira, Rio Grande 
do Sul, Brazil. Carn. Mus. Cat. 61.5868. Gills of female (No. 9). 

Fig. 2. Castalina nehringi Von Ihering. from Rio Tieté, Itapura, Sao Paulo, Brazil. 
Carn. Mus. Cat. No. 61.5120. Gills of half-grown female (No. 1). 

Fic. 3. Monocondylea lentiformis Lea, from Rio Uruguay, Uruguayana, Rio 
Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5841. 

Fra. 3a. Gills of male (No. 1). — 

Fia. 3b. Gills of female (No. 4). 

Fic. 4. Anodontites clessini (Fischer), from Rio Vaccahy-mirim, Santa Maria, 
Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5820. 

Fia. 4a. Gills of male (No. 12) (Shell of this specimen figured on Plate XLI, fig. 4, 

and Plate XLII, fig. 1). 
Fic. 4b. Gills of female (No. 11) (Shell of this specimen figured on Plate XLII, 
fig. 2). 

Fic. 5. Diplodon hasemani Ortmann, from Rio Guaporé, near Rio Sao Simao, 
Matto Grosso, Brazil, Carn. Mus. Cat. No. 61.5857. Section of gills of gravid female 
(No. 5). 

Fic. 6. Diplodon imitator Ortmann, from Rio Vaccahy-mirim, Santa Maria, Rio 
Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.9284. Section of gills of female (No. 
33) (Shell of this specimen figured on Plate XO, fie 7): 

Fic. 7. Diplodon decipiens Ortmann, from creek (tributary to Rio Iguasst), Ser- 
rinha, Parana, Brazil. Carn. Mus. Cat. No. 61.9253. Section of gills of gravid female 
(No. 5). 


MEMOIRS CARNEGIE Museum, VOL. VIII. PLATE XLVII. 


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Anatomy or DipLopon, CasTaLia, MonoconDYLH&A, ANODONTITES. 


670 MEMOIRS OF THE CARNEGIE MUSEUM. 


EXPLANATION OF PLATE XLVIII. 


HORIZONTAL SECTIONS OF GILLS OF DrPLODON PAULISTA (VON IHERING), DIPLODON 
MOGYMIRIM ORTMANN, DipLopon GRATUS (LEA), DIPLODON DECEPTUS 
(Simpson), CASTALINA NEHRINGI Von IHERING, FossuLA FOSSICULI— 

rFERA (D’OrBIGNY), MONOCONDYLHA MINUANA D’ORBIGNY, 
AND ANODONTITES PATAGONICA RUBICUNDA (LEA); 
much enlarged; inner gill to the left, 


outer gill to the right. 


Fic. 1. Diplodon paulista (Von Ihering), from creek (tributary to Rio Mogy 
Guasst), Mogy Mirim, Sao Paulo, Brazil. Carn. Mus. Cat. No. 61.9256. Section of 
gills of gravid female (No. 3). 

Fig. 2. Diplodon mogymirim Ortmann, from creek (tributary to Rio Mogy Guasst), 
Mogy Mirim, Sao Paulo, Brazil. Carn. Mus. Cat. No. 61.9260. 

Fie. 2a. Section of gills of female (No. 45). 

Fia. 2b Section of gills of gravid female (No. 4). 

Fia. 38. Diplodon gratus (Lea), from Rio Uruguay, Uruguayana, Rio Grande do 
Sul, Brazil. Carn. Mus. Cat. No. 61.5866. 

Fia. 8a. Section of gills of male (No. 19). 

Fia. 8b. Section of gills of female (No. 20). 

Fria. 4. Diplodon deceptus (Simpson), from Rio Jacuhy, Cachoeira, Rio Grande 
do Sul, Brazil. Carn. Mus. Cat. No. 61.5868. Section of gills of half-grown female 
(No. 6) (Shell of this specimen figured on Plate XX XIX, fig. 4). 

Fia. 5. Castalina nehringi Von Thering, from Rio Tieté, Itapura, Sao Paulo, Brazil. 
Carn. Mus. Cat. No. 61.5120. Section of gills of gravid female (No. 5). 

Fria. 6. Fossula fossiculifera (D’Orbigny), from Rio Tieté, Itapura, Sao Paulo, 
Brazil. Carn. Mus. Cat. No. 61.5840. Section of gills of female. 

Fia. 7. Monocondylea minuana D’Orbigny, from Rio Uruguay, Uruguayana, 
Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5848. 

Fia. 7a. Section of gills of male (No. 5). 

Fie. 7b. Section of gills of gravid female (No. 6). 

Fia. 8. Anodontites patagonica rubicunda (Lea), from Rio Cacequy, Cacequy, 
Rio Grande do Sul, Brazil. Carn. Mus. Cat. No. 61.5810. Section of gills of female. 


MEMOIRS CARNEGIE MUSEUM, VOL. VIII. PLATE XLVIII. 


Anatomy oF DrpLtopon, CastTaLina, FossuLA, MonoconpyL@A, and ANODONTITES. 


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